Problem: A woman’s cellular email service stopped working. I removed her account and tried re-adding it, and there was the same server connectivity error. I tried adding her account on a phone, but I received the same results. Then, I checked services on the exchange server, and all auto start services were running. I checked MX toolbox to run a server connectivity test, though I could not find the issue.
Solution: I finally ran the test connectivity tool from Microsoft which led to an IIS application not functioning. I started the MSExchangeSyncAppPool app and setup the user’s email on a phone. I emailed the end user with an update and all was working.