This a free web based tool to test whether your exchange servers are working fine. This will make sure about any resource records issues or naming resolution issues or unreachable issues
Tests here are:
Microsoft Exchange ActiveSync Connectivity Tests
Exchange ActiveSync
ActiveSync AutoDiscover
Microsoft Exchange Web Services Connectivity Tests
Synchronization, Notification, Availability, and OOF
Service Account Access (Developers)
Microsoft Office Outlook Connectivity Tests
Outlook Anywhere (RPC over HTTP)
Outlook AutoDiscover
Internet Email Tests
Inbound SMTP Email
Outbound SMTP Email
Click here to there: https://www.testexchangeconnectivity.com/

