We've been facing some problems pertaining to expiring user passwords, causing "server unavailable" login problems for Outlook Outlook 2007 and 2010 clients on exchange 2013. The quick fix to this was to delete the profile in control panel > mail32, rebuild, and install the certificate again (i don't remember where, but I suspect user profile).
Still, this is a problem that appeared every time passwords expired and was causing serious service outages for our users.
Trying to get to the root of the problem, i figured this was related to certificates being generated at the user level with the user password as the key, and when the password expired, so did the certificate.
To fix this, I setup a local standalone root CA to generate a trusted certificate and applied it via GPO on the "computer > windows settings > security > trusted" level for all computers and servers.
A quick test by changing the password on a previously problematic profile seems to indicate success.
User updates their password on logon. This works fine. The user logs into the local machine, opens outlook and is prompted for the new password and also logs in fine (no need to install new certificates).
Is this solved or am I missing something?