We have two email domains on our SBS 2008 server running Exchange 2007. The primary domain is generally accessed over LAN with Outlook 2010 in cached exchange mode. No issues there. The 2nd domain is a sister company that is primarily accessed with Outlook 2010 via RPC over HTTP, and a couple of accounts use POP3.
The problem is, the external clients are getting cert mismatch errors that actually freeze Outlook and the connection to the server drops. I have to reset IIS in the server to get mail to flow again, and it happens several times a day.
We have a Godaddy SSL cert with our primary domain name, internal domain name, autodiscover, etc. It wasn't an issue until the owner of the sister company moved the second domain to a new host that used cpanel which supports the autodiscover srv record. Because the cert is issued to the primary, autodiscover throws the error every 2 or three minutes.
I tried configuring Outlook 2010 to suppress name checking with a registry key, but no joy.
Do I need to buy a UCC cert with multiple domain names, and if so, can I successfully import such a cert into SBS 2008 since it isn't supported in the trusted cert authorities by default?