Here are two ways of testing Exchange ActiveSync and RPC / HTTPS

The AccessMyLan ActiveSync Tester (https://store.accessmylan.com/main/diagnostic-tools?pos=nav )simulates an ActiveSync client and provides a detailed diagnostic report with possible solution options. The tool can identify:

Host connectivity and name resolution (DNS) problems SSL / Certificate issues Exchange Server / ActiveSync configuration issues User configuration issues

Alternatively, you can use the online (Micrososft recommended/implemented) tool here:

https://www.testexchangeconnectivity.com/