Outlook clients cannot connect to exchange 2010


  • Hi,

    I am having problems getting my outlook (2007 & 2010) clients to connect to exchange 2010. I have all the server roles on a single server, with AD on a separate server, both running server 2008 R2. I was running exchange 2007 prior to this, to migrate I commissioned a new server with exchange 2010, moved all the mailboxes across and then decommissioned the old server. Everything has been working great until the other day, and now no clients can connect.

    Interestingly I had 2 outlook 2010 clients operating in cached mode that could still connect, but after deleting the profile and trying to reconfigure one of them, it now cannot connect just like the 2007 clients. On the one 2010 client that does still work, there are some oddities, such as trying to create or update contacts will not complete. The error messages when trying to configure the exchange account are: "The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action." and "The name cannot be resolved. The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action."

    Also I have multiple activesync devices that can still configure and connect to the server, and the outlook web app functions properly.

    Things I have tried:

    • Rebooting the server
    • set-mailboxdatabase -identity "name_of_mailbox_database" -RpcClientAccessServer FQDN_of_CAS_server
    • Verifying all DNS records for the server
    • Disabled windows firewall on the server

    I am having difficulty finding any problems on the server, everything seems fine and dandy in the management console, and OWA and activesync work fine...


    Any suggestions would be great, thanks,

    Aaron Trout

    Wednesday, May 12, 2010 8:16 AM


All replies

  • I know this normally relates to Outlook 2003, but you haven't changed the encryption setting on the CAS by mistake have you?  See this post for details (the 'encryption' heading right at the start)

    Neil Hobson, Exchange MVP
    • Proposed as answer by emma.yoyo Tuesday, May 18, 2010 1:44 AM
    • Marked as answer by emma.yoyo Wednesday, May 19, 2010 1:27 AM
    Wednesday, May 12, 2010 9:04 AM
  • Hi Aaron,

    How about your question now?

    Frank Wang
    Monday, May 17, 2010 2:02 AM
  • I have this same issue and have done all of the above.  rpc encryption is off by default in exchange 2010 sp1.

    I can enter my 2007 cas server name when setting up outlook and it'll redirect to the 2010 cas, however if I type in, or use the autodiscover to use exchange 2010 cas, mailbox cannot be found.

    Been spending days on this.  


    not using a cas array, and the cas setting in the mailbox is correct.

    dns resolves properly

    no firewall

    tested auto discover and that works properly.



    Friday, January 07, 2011 7:17 PM