I recently upgraded from EXCH 2007 to EXCH 2013. We now get a "Security Alert" window upon opening Outlook that contains the following information:
{fqdn}
Information you exchange with this site cannot be viewed or changed by others. However, there is a problem with the site's security certificate.
[GREEN check] The security cert is from a trusted certifying authority.
[GREEN check] The security cert date is valid.
[RED "X"] The name of the security cert is invalid or does not match the name of the site.
Do you want to proceed?
What makes this issue so particular is that we have a combination of Outlook 2010 and 2013 installations in the office. When working with the installer and MSFT during installation, an attempt was made to fix the cert issue on the server. The result was that it worked on 2013 clients but not 2010 clients (they would not connect). We also DO NOT have an issue with either OWA or Active Sync clients. The problem seems to be limited to the inward facing cert. The work around so far has been to have all clients endure seeing the Security Alert shown above. You simply click yes (to proceed), the alert goes away and the client connects to EXCH. On some occasions from a cold startup, a client will not connect to EXCH, requiring a full reboot of the computer.
As for the cert, I have already clicked "View Certificate" and I've installed it successfully. But the Security Alert continues to be displayed every time Outlook is opened.