We have been having a ton of certificate errors, due to our internal domain being "domain.local", and only having a single Exchange server with a wildcard cert "*.domain.local". To ensure that all Outlook users would connect directly to the external address (which had the proper certificate), I changed all of the internal/external settings in these instructions (http://exchangeserverpro.com/avoiding-exchange-2013-server-names-ssl-certificates/
) to https://external.domain.com/_____.
Tested it on a few machines, no problems. The next day (today), getting 50% of users internally reporting that they cannot connect - keeps popping up user/pass window... Try to authenticate (domain\user and applicable password), but only get this error: "The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action." So far, no issue configuring externally, and the "Remote Connectivity Analyzer" shows no issues in any category.
OWA works fine, and as I mentioned, about 50% of users work normally after reboot. Stumped - can anyone help?