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For users on OCS 2007 or OCS 2007 R2 an error will show in communicator stating the error below:

This is most often seen with users located on Exchange 2007, but can also occur for Exchange 2003 users

Exchange Connection Error

Communicator could not retrieve calendar or Out of Office information from Exchange Web Services. Communicator will automatically continue to retry. If this problem persists, contact your system administrator.

There can be several reasons for this, so to find the error follow these steps:

  • Verify that you have SAN certificates configured for you Exchange website
  • Verify Auth. settings on Exchange websites (default should do)
  • Check your Client computers proxy settings (should bypass proxy for these requests)
  • Make sure that you Outlook and Communicator clients are up to date (this is very important)
  • Make sure that the web server certificate CA CRL can be accessed (apparently Communicator contacts the certificate issuer (in most cases an internal Windows CA) for the CRL, and will show this error if it fails)

When troubleshooting, always test if there is a difference between access internal and external

Post comments if you need any assistance

Rasmus

0 Responses to Communicator Error: Exchange Connection Error

  • can you be more specific on the SAN certificates for Exchange websites? I am having this problem, and I’m pretty sure it is a cert issue, but I am not quite sure of all the specifics I need for creating the cert.

  • Hi Paul

    There is nothing special about the certificates for Exchange 2007 when using OCS. You need to implement a certificate with SAN names to secure all the “names” of your Exchange server. The MS Exchange Team has a good explanation about this, that you can use as a guide: http://msexchangeteam.com/archive/2007/02/19/435472.aspx

    If you are still stuck, let me know more exactly where.

  • i checked all of the above, what fixed it for me for starting outlook with
    outlook /cleanfreebusy

  • Verify that you have SAN certificates configured for you Exchange website
    Verify Auth. settings on Exchange websites (default should do)
    Check your Client computers proxy settings (should bypass proxy for these requests)
    Make sure that you Outlook and Communicator clients are up to date (this is very important)
    Make sure that the web server certificate CA CRL can be accessed (apparently Communicator contacts the certificate issuer (in most cases an internal Windows CA) for the CRL, and will show this error if it fails)

    But could you please explain how do I do all these

  • When you see the “Exchange Connection” error, try to schedule a meeting through Outlook and see if free-busy information is available for contacts. If you see the free-busy information the Exchange server is working correctly. When Communicator is first launched it should prompt you to login to your Exchange mailbox. If you cancel out of this login Communicator will not be able to pull calendar information. To test this, exit completely out of Communicator and then re-launch it and make sure you enter you login information in each login prompt.

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