A listing in numeric order of Microsoft Dial-Up Networking (DUNS) Error codes with the Microsoft error message follows. If there's a hyperlink, you can follow it for more information on what to do about the error. If you are getting an error that does not have more information here, please let me know! The list includes error codes for Windows 95, 98, Me, NT, 2000, XP, and Vista.
In later versions of operating systems (NT, 2000, XP and Vista) some of the errors can occur for connections other than traditional dial-up modem connections: they may occur with DSL and VPN (virtual private networking) connections that do not involve dial-up.
NOTE: Some solutions indicate to re-install DUNs and/or TCP/IP. See this Microsoft KB article for Win 95/98 instructions to Remove & Re-install DUNS & TCP/IP. Newer versions of Windows don't allow DUNS uninstall: see Reset DUNS (TCP/IP) in Windows 2000 & XP.
Windows Vista: Dialing directly from the 'Connect To' menu or other shortcuts will not display DUNs error codes - instead, particularly large and unhelpful dialog boxes are shown as detailed here. In order to see any DUNs error codes, you must dial from the 'Manage Network Connections' Window.
ALSO SEE: Connectoids. In many cases, DUNs Errors can be solved by correcting the properties for your dial-up networking connections.
ERROR 50 - The request is not supported.
600 - An operation is pending.
601 - The port handle is invalid.
602 - The port is already open.
603 - Caller's buffer is too small.
604 - Wrong information specified.
605 - Cannot set port information.
606 - The port is not connected.
607 - The event is invalid.
608 - The device does not exist.
609 - The device type does not exist.
610 - The buffer is invalid.
611 - The route is not available.
612 - The route is not allocated.
613 - Invalid compression specified.
614 - Out of buffers.
615 - The port was not found.
616 - An asynchronous request is pending.
617 - The port or device is already disconnecting.
618 - The port is not open.
619 - The port is disconnected.
620 - There are no endpoints.
621 - Cannot open the phone book file.
622 - Cannot load the phone book file.
623 - Cannot find the phone book entry.
624 - Cannot write the phone book file.
625 - Invalid information found in the phone book.
626 - Cannot load a string.
627 - Cannot find key.
628 - The port was disconnected.
629 - The port was disconnected by the remote machine.
630 - The port was disconnected due to hardware failure.
631 - The port was disconnected by the user.
632 - The structure size is incorrect.
633 - The port is already in use or is not configured for Remote Access dialout.
634 - Cannot register your computer on the remote network.
635 - Unknown error.
636 - The wrong device is attached to the port.
637 - The string could not be converted.
638 - The request has timed out.
639 - No asynchronous net available.
640 - A NetBIOS error has occurred.
641 - The server cannot allocate NetBIOS resources needed to support the client.
642 - One of your NetBIOS names is already registered on the remote network.
643 - A network adapter at the server failed.
644 - You will not receive network message popups.
645 - Internal authentication error.
646 - The account is not permitted to log on at this time of day.
647 - The account is disabled.
648 - The password has expired.
649 - The account does not have Remote Access permission.
650 - The Remote Access server is not responding.
651 - Your modem (or other connecting device) has reported an error.
652 - Unrecognized response from the device.
653 - A macro required by the device was not found in the device .INF file section.
654 - A command or response in the device .INF file section refers to an undefined macro
655 - The
656 - The
657 - The device .INF file could not be opened.
658 - The device name in the device .INF or media .INI file is too long.
659 - The media .INI file refers to an unknown device name.
660 - The device .INF file contains no responses for the command.
661 - The device .INF file is missing a command.
662 - Attempted to set a macro not listed in device .INF file section.
663 - The media .INI file refers to an unknown device type.
664 - Cannot allocate memory.
665 - The port is not configured for Remote Access.
666 - Your modem (or other connecting device) is not functioning.
667 - Cannot read the media .INI file.
668 - The connection dropped.
669 - The usage parameter in the media .INI file is invalid.
670 - Cannot read the section name from the media .INI file.
671 - Cannot read the device type from the media .INI file.
672 - Cannot read the device name from the media .INI file.
673 - Cannot read the usage from the media .INI file.
674 - Cannot read the maximum connection BPS rate from the media .INI file.
675 - Cannot read the maximum carrier BPS rate from the media .INI file.
676 - The line is busy.
677 - A person answered instead of a modem.
678 - There is no answer.
679 - Cannot detect carrier.
680 - There is no dial tone.
681 - General error reported by device.
682 - ERROR WRITING SECTIONNAME
683 - ERROR WRITING DEVICETYPE
684 - ERROR WRITING DEVICENAME
685 - ERROR WRITING MAXCONNECTBPS
686 - ERROR WRITING MAXCARRIERBPS
687 - ERROR WRITING USAGE
688 - ERROR WRITING DEFAULTOFF
689 - ERROR READING DEFAULTOFF
690 - ERROR EMPTY INI FILE
691 - Access denied because username and/or password is invalid on the domain.
692 - Hardware failure in port or attached device.
693 - ERROR NOT BINARY MACRO
694 - ERROR DCB NOT FOUND
695 - ERROR STATE MACHINES NOT STARTED
696 - ERROR STATE MACHINES ALREADY STARTED
697 - ERROR PARTIAL RESPONSE LOOPING
698 - A response keyname in the device .INF file is not in the expected format.
699 - The device response caused buffer overflow.
700 - The expanded command in the device .INF file is too long.
701 - The device moved to a BPS rate not supported by the COM driver.
702 - Device response received when none expected.
703 - ERROR INTERACTIVE MODE
704 - ERROR BAD CALLBACK NUMBER
705 - ERROR INVALID AUTH STATE
706 - ERROR WRITING INITBPS
707 - X.25 diagnostic indication.
708 - The account has expired.
709 - Error changing password on domain.
710 - Serial overrun errors were detected while communicating with your modem.
711 - RasMan initialization failure. Check the event log.
712 - Biplex port is initializing. Wait a few seconds and redial.
713 - No active ISDN lines are available.
714 - Not enough ISDN channels are available to make the call.
715 - Too many errors occurred because of poor phone line quality.
716 - The Remote Access IP configuration is unusable.
717 - No IP addresses are available in the static pool of Remote Access IP addresses.
718 - PPP timeout.
719 - PPP terminated by remote machine.
720 - No PPP control protocols configured.
721 - Remote PPP peer is not responding.
722 - The PPP packet is invalid.
723 - The phone number, including prefix and suffix, is too long.
724 - The IPX protocol cannot dial-out on the port because the computer is an IPX router.
725 The IPX protocol cannot dial-in on the port because the IPX router is not installed.
726 - The IPX protocol cannot be used for dial-out on more than one port at a time.
727 - Cannot access TCPCFG.DLL.
728 - Cannot find an IP adapter bound to Remote Access.
729 - SLIP cannot be used unless the IP protocol is installed.
730 - Computer registration is not complete.
731 - The protocol is not configured.
732 - The PPP negotiation is not converging.
733 - The PPP control protocol for this network protocol is not available on the server.
734 - The PPP link control protocol terminated.
735 - The requested address was rejected by the server.
736 - The remote computer terminated the control protocol.
737 - Loopback detected.
738 - The server did not assign an address.
739 - The remote server cannot use the Windows NT encrypted password.
740 - The TAPI devices configured for Remote Access failed to initialize or were not installed correctly.
741 - The local computer does not support encryption.
742 - The remote server does not support encryption.
743 - The remote server requires encryption.
744 - Cannot use the IPX net number assigned by the remote server. Check the event log.
745 - An essential file is missing. Re-install Dial-Up Networking
751 - The callback number contains an invalid character. Only the following characters are allowed: 0 to 9, T, P, W, (,), -, @, and space.
752 - A syntax error was encountered while processing a script.
753 - The connection could not be disconnected because it was created by the multi-protocol router.
754 - The system could not find the multi-link bundle.
755 - The system cannot perform automated dial because this entry has a custom dialer. specified.
756 - This connection is already being dialed.
757 - Remote access services could not be started automatically. Additional information is provided in the event log.
758 - Internet connection sharing is already enabled on the connection.
760 - An error occurred while routing capabilities were being enabled.
761 - An error occurred while Internet connection sharing was being enabled for the connection.
763 - Internet connection sharing cannot be enabled. There are two or more LAN connections in addition to the connection to be shared.
764 - No smart card reader is installed.
765 - Internet connection sharing cannot be enabled. A LAN connection is already configured with the IP address required for automatic IP addressing.
766 - The system could not find any certificate.
767 - Internet connection sharing cannot be enabled. The LAN connection selected on the private network has more than one IP address configured. Reconfigure the LAN connection with a single IP address before enabling Internet connection sharing.
768 - The connection attempt failed because of failure to encrypt data.
769 - The specified destination is not reachable.
770 - The remote machine rejected the connection attempt.
771 - The connection attempt failed because the network is busy.
772 - The remote computer's network hardware is incompatible with the type of call requested.
773 - The connection attempt failed because the destination number has changed.
774 - The connection attempt failed because of a temporary failure. Try connecting again.
775 - The call was blocked by the remote computer.
776 - The call could not be connected because the destination has invoked the Do Not Disturb feature.
777 - The connection attempt failed because the modem (or other connecting device) on the remote computer is out of order.
778 - It was not possible to verify the identity of the server.
779 - To dial out using this connection, you must use a smart card.
780 - An attempted function is not valid for this connection.
781 - The encryption attempt failed because no valid certificate was found.
782 - Network Address Translation (NAT) is currently installed as a routing protocol, and must be removed before enabling Internet Connection Sharing.
783 - Internet Connection Sharing cannot be enabled. The LAN connection selected as the private network is either not present, or is disconnected from the network. Please ensure that the LAN adapter is connected before enabling Internet Connection Sharing.
784 - You cannot dial using this connection at logon time, because it is configured to use a user name different than the one on the smart card. If you want to use it at logon time, you must configure it to use the user name on the smart card.
785 - You cannot dial using this connection at logon time, because it is not configured to use a smart card. If you want to use it at logon time, you must edit the properties of this connection so that it uses a smart card.
786 - The L2TP connection attempt failed because there is no valid machine certificate on your computer for security authentication.
787 - The L2TP connection attempt failed because the security layer could not authenticate the remote computer.
788 - The L2TP connection attempt failed because the security layer could not negotiate compatible parameters with the remote computer.
789 - The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.
790 - The L2TP connection attempt failed because certificate validation on the remote computer failed.
791 - The L2TP connection attempt failed because security policy for the connection was not found.
792 - The L2TP Connection Attempt failed because security negotiation timed out.
793 - The L2TP connection attempt failed because an error occurred while negotiating security.
794 - The Framed Protocol RADIUS attribute for this user is not PPP.
795 - The Tunnel Type RADIUS attribute for this user is not correct.
796 - The Service Type RADIUS attribute for this user is neither Framed nor Callback Framed.
797 - The modem could not be found.
798 - A certificate could not be found that can be used with this Extensible Authentication Protocol.
799 - Internet Connection Sharing (ICS) cannot be enabled due to an IP address conflict on the network. ICS requires the host be configured to use 192.168.0.1. Please ensure that no other client on the network is configured to use 192.168.0.1.
800 - Unable to establish the VPN connection. The VPN server may be un-reachable, or security parameters may not be configured properly for this connection.
801 - This connection is configured to validate the identity of the access server, but Windows cannot verify the digital certificate sent by the server.
ERROR CODES 802 - 827 ARE NEW TO WINDOWS VISTA
802 - The card supplied was not recognized. Please check that the card is inserted correctly, and fits tightly.
803 - The PEAP configuration stored in the session cookie does not match the current session configuration.
804 - The PEAP identity stored in the session cookie does not match the current identity.
805 - You cannot dial using this connection at logon time, because it is configured to use logged on user's credentials.
806 - A connection between your computer and the VPN server has been started, but the VPN connection cannot be completed. The most common cause for this is that at least one Internet device (for example, a firewall or a router) between your computer and the VPN server is not configured to allow Generic Routing Encapsulation (GRE) protocol packets. If the problem persists, contact your network administrator or Internet service provider.
807 - The network connection between your computer and the VPN server was interrupted. This can be caused by a problem in the VPN transmission and is commonly the result of internet latency or simply that your VPN server has reached capacity. Please try to reconnect to the VPN server. If this problem persists, contact the VPN administrator and analyze quality of network connectivity.
808 - The network connection between your computer and the VPN server could not be established because the remote server refused the connection. This is typically caused by a mismatch between the server's configuration and your connection settings. Please contact the remote server's Administrator to verify the server configuration and your connection settings.
809 - The network connection between your computer and the VPN server could not be established because the remote server is not responding. This could be because one of the network devices (e.g., firewalls, NAT, routers, etc.) between your computer and the remote server is not configured to allow VPN connections. Please contact your Administrator or your service provider to determine which device may be causing the problem.
810 - A network connection between your computer and the VPN server was started, but the VPN connection was not completed. This is typically caused by the use of an incorrect or expired certificate for authentication between the client and the server. Please contact your Administrator to ensure that the certificate being used for authentication is valid.
811 - The network connection between your computer and the VPN server could not be established because the remote server is not responding. This is typically caused by a pre-shared key problem between the client and server. A pre-shared key is used to guarantee you are who you say you are in an IP Security (IPSec) communication cycle. Please get the assistance of your administrator to determine where the pre-shared key problem is originating.
812 - The connection was prevented because of a policy configured on your RAS/VPN server. Specifically, the authentication method used by the server to verify your username and password may not match the authentication method configured in your connection profile. Please contact the Administrator of the RAS server and notify them of this error.
813 - You have attempted to establish a second broadband connection while a previous broadband connection is already established using the same device or port. Please disconnect the earlier connection and then re-establish the connection.
814 - The underlying Ethernet connectivity required for the broadband connection was not found. Please install and enable the Ethernet adapter on your computer via the Network Connections folder before attempting this connection.
815 - Failed to connect.
815 - The broadband network connection could not be established on your computer because the remote server is not responding. This could be caused by an invalid value for the 'Service Name' field for this connection. Please contact your Internet Service Provider and inquire about the correct value for this field and update it in the Connection Properties.
816 - A feature or setting you have tried to enable is no longer supported by the remote access service.
817 - Cannot delete a connection while it is connected.
818 - The Network Access Protection (NAP) enforcement client could not create system resources for remote access connections. Some network services or resources might not be available. If the problem persists, disconnect and retry the remote access connection or contact the administrator for the remote access server.
819 - The Network Access Protection Agent (NAP Agent) service has been disabled or is not installed on this computer. Some network services or resources might not be available. If the problem persists, disconnect and retry the remote access connection or contact the administrator for the remote access server.
820 - The Network Access Protection (NAP) enforcement client failed to register with the Network Access Protection Agent (NAP Agent) service. Some network services or resources might not be available. If the problem persists, disconnect and retry the remote access connection or contact the administrator for the remote access server.
821 - The Network Access Protection (NAP) enforcement client was unable to process the request because the remote access connection does not exist. Retry the remote access connection. If the problem persists, make sure that you can connect to the Internet, and then contact the administrator for the remote access server.
822 - The Network Access Protection (NAP) enforcement client did not respond. Some network services or resources might not be available. If the problem persists, disconnect and retry the remote access connection or contact the administrator for the remote access server.
823 - Received Crypto-Binding TLV is invalid.
824 - Crypto-Binding TLV is not received.
825 - Point-to-Point Tunnelling Protocol (PPTP) is incompatible with IPv6. Change the type of virtual private network to Layer Two Tunnelling Protocol (L2TP)
826 - EAPTLS validation of the cached credentials failed. Please discard cached credentials.
827 - The L2TP/IPsec connection cannot be completed because the IKE and AuthIP IPSec Keying Modules service and/or the Base Filtering Engine service is not running. These services are required to establish an L2TP/IPSec connection. Please ensure that these services have been started before dialling the connection
900 - The router is not running.
901 - The interface is already connected.
902 - The specified protocol identifier is not known to the router.
903 - The Demand-dial Interface Manager is not running.
904 - An interface with this name is already registered with the router.
905 - An interface with this name is not registered with the router.
906 - The interface is not connected.
907 - The specified protocol is stopping.
908 - The interface is connected and hence cannot be deleted.
909 - The interface credentials have not been set.
910 - This interface is already in the process of connecting.
911 - An update of routing information on this interface is already in progress.
912 - The interface configuration in invalid. There is already another interface that is connected to the same interface on the remote router.
913 - A Remote Access Client attempted to connect over a port that was reserved for Routers only.
914 - A Demand Dial Router attempted to connect over a port that was reserved for Remote Access Clients only.
915 - The client interface with this name already exists and is currently connected.
916 - The interface is in a disabled state.
917 - The authentication protocol was rejected by the remote peer.
918 - There are no authentication protocols available for use.
919 - The remote computer refused to be authenticated using the configured authentication protocol. The line has been disconnected.
920 - The remote account does not have Remote Access permission.
921 - The remote account has expired.
922 - The remote account is disabled.
923 - The remote account is not permitted to logon at this time of day.
924 - Access was denied to the remote peer because username and/or password is invalid on the domain.
925 - There are no routing enabled ports available for use by this demand dial interface.
926 - The port has been disconnected due to inactivity.
927 The interface is not reachable at this time.
928 The Demand Dial service is in a paused state.
929 The interface has been disconnected by the administrator.
930 The authentication server did not respond to authentication requests in a timely fashion.
931 The maximum number of ports allowed for use in the multilinked connection has been reached.
932 The connection time limit for the user has been reached.
933 The maximum limit on the number of LAN interfaces supported has been reached.
934 The maximum limit on the number of Demand Dial interfaces supported has been reached.
935 The maximum limit on the number of Remote Access clients supported has been reached.
936 The port has been disconnected due to the BAP policy.
937 Because another connection of your type is in use, the incoming connection cannot accept your connection request.
938 No RADIUS servers were located on the network.
939 An invalid response was received from the RADIUS authentication server. Make sure that the case sensitive secret password for the RADIUS server is set correctly.
940 You do not have permission to connect at this time.
941 You do not have permission to connect using the current device type.
942 You do not have permission to connect using the selected authentication protocol.
943 BAP is required for this user.
944 The interface is not allowed to connect at this time.
945 The saved router configuration is incompatible with the current router.
946 RemoteAccess has detected older format user accounts that will not be migrated automatically. To migrate these manually, run XXXX.
948 The transport is already installed with the router.
949 Received invalid signature length in packet from RADIUS server.
950 Received invalid signature in packet from RADIUS server.
951 Did not receive signature along with EAPMessage from RADIUS server.
952 Received packet with invalid length or Id from RADIUS server.
953 Received packet with attribute with invalid length from RADIUS server.
954 Received invalid packet from RADIUS server.
955 Authenticator does not match in packet from RADIUS server.
