I am in the process of migrating from exchange 2003 to 2010 , both are running in coexsistence.
After the new exchange installation on 2008 R2 was done i noticed on EMC by default a cert was created.When then moved my mailbox over from 2003 to 2010 (local move) my active sync stopped working.
I created a new certreq with the following error.
There is a problem with the proxy server's security certificate, %s. The name on the security certificate is invalid or does not match the name of the site