Error message when you click the "Join the Meeting" link in the e-mail message that you receive from the Web Conference session presenter in Communications Server: "An error occurred verifying the server's certificate"

You receive an e-mail message from a Web Conference session presenter in Microsoft Office Communications Server. When you click the Join the Meeting link, you receive the following error message:Additionally, you cannot join the session.

This issue occurs because the computer that is hosting the Microsoft Office Live Meeting 2007 attendee does not have the correct certificate in the Trusted Root Certification Authorities store. This certificate must be signed by the same certification authority that provides the Web server and the certificate to the server that is running Microsoft Office Communications Server Standard Edition or to the Microsoft Office Communications Server Enterprise Edition pool.

To resolve this issue, follow these steps:

1. Obtain the correct certificate from the same certification authority that provides the Web server and the certificate to the Communications Server Standard Edition server or to the Communications Server Enterprise Edition pool.
2. Open Microsoft Internet Explorer.
3. On the Tools menu, click Internet Options.
4. Click the Content tab, and then click Certificates.
5. Click Import, and then complete the Certificate Import Wizard. Provide the location of the certificate file.

You can confirm this issue by enabling logging for the Live Meeting 2007 session presenter. To do this, follow these steps.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Tracing\uccp\LiveMeeting
3. Double-click the EnableFileTracing registry entry, type 1 in the Value data box, and then click OK.
4. Close Registry Editor.
5. Click the Join the Meeting link to reproduce the error. In the \%USERPROFILE%\Tracing folder, locate the LiveMeeting-uccp-0.log file. The following error message is logged in the file:
   SECURE_SOCKET: negotiation failed: 80090325