Microsoft Exchange 2010 Certificate Error

We use Microsoft SBS 2011 which has Exchange 2010. We recently renewed our Comodo UC certificate that gives us SSL when connecting to OWA remotely but something has gone wrong when this was installed. Remote OWA seems to work fine but we can no longer connect internally on the LAN to the server using IMAP, Outlook is working fine on our PC’s on the local network but we have some other local systems that use IMAP to read email and these get a timeout error on port 993. This has all seemed to have started from the installation of the certificate and the subsequent attempts by myself to fix it. What I need is: Check that the Comodo SSL UC certificate is correctly installed. Fix the potential certificate problem that is effecting internal IMAP connections from working. When quoting please quote reference PB2013 so that we know you’ve read the job spec. Thanks