When you attempt to connect to your Internet service provider (ISP), you may receive one of the following error:

Error 691: Access was denied because the user name and/or password was invalid on the domain.

Cause

This behavior can occur if any of the following conditions are true :

• The settings for your dial-up connection to your ISP are configured incorrectly.
• The dial-up connection’s security option is incorrectly configured to use the require secured password setting.
• Your ISP’s Point-to-Point Protocol (PPP) server is not functioning properly.
• You type an incorrect user name or password.

Resolution

To resolve this issue (or issues), use the following methods, as necessary, in the order presented. After you finish each method, check to see whether you can connect to your ISP successfully.

NOTE : You must be logged on as an administrator or a member of the Administrators group to complete these procedures. If your computer is connected to a network, network policy settings may also prevent you from completing these procedures.

Verify Your User Name and Password :

If the problem continues after you follow the steps in this article, try the following procedures. These procedures may help you determine the cause of the problem, or they may resolve the problem.

1. Make sure that the CAPS LOCK key has not been accidentally pressed and engaged.
2. Click Start, point to Connect To, and then click your dial-up connection.
3. In the Connect dialog box, verify that your user name and password are correctly typed in the User name and Password boxes as provided by your ISP, and then click Dial.NOTE: If you are not sure what your user name and password are, contact your ISP for assistance.

If you try to establish a Point-to-Point Protocol (PPP) dial-up connection, you may receive the following error message :

Error 734: The PPP link control protocol was terminated.

Cause

This issue may occur if either of the following conditions are true :

• • Multi-link negotiation is turned on for the single-link connection.

OR

• The dial-up connection security configuration is incorrectly configured to use the Require secured password setting.

Resolution

To resolve this issue , follow these steps :

• Click Start, point to Settings, and then click Network and Dial-up Connections.
  NOTE: For Windows Server 2003, click Start, point to Control Panel and then point to Network Connections.
• Right-click the appropriate dial-up networking connection and then click Properties.
• Click the Networking tab and then click Settings.
• Click to clear the Negotiate multi-link for single link connections check box (if it is selected).
• Click OK, and then click OK.
• Double-click the connection and then click Dial.
  1. If this procedure resolves the issue and you can establish a dial-up connection, you do not have to follow the remaining steps in this article.
  2. If this does not resolve the issue and you cannot establish a dial-up connection, go to step 7 to continue to troubleshoot this issue.
• Right-click the connection, and then click Properties.
• Click the Security tab.
• Under Security options, click Allow unsecured password in the Validate my identity as follows box, and then click OK.
• Double-click the connection, and then click Dial to verify that you can establish a dial-up connection.