This is a new Exchange 2016 installation on an internally hosted Windows Server 2016.
DNS (Including Autodiscover) is set up.
3rd party SSL certificate is set up.
OWA is working fine. Browser shows secure connection. (Ie. using https://servername.domain.com/OWA
Outlook 2010/2013/2016 connection to mailbox is working fine (internally and externally). Accounts are easily set up via Autodiscover and no SSL errors during account set up.
Send/receive working fine via Outlook and OWA.
When I try connecting via Exchange Activesync on iOS or Android it fails to connect.
iOS says "Unable to verify account information."
Android says "Cannot connect to server"
I checked Activesync status in Exchange Administration console. It's turned on by default and I did not change the settings.
I used the Microsoft Connectivity Analyzer to test Exchange ActiveSync.
Autodiscover settings weren't obtained when the Autodiscover POST request was sent.
The Microsoft Connectivity Analyzer failed to obtain an Autodiscover XML response.
I reseached this and tried troubleshooting steps from other forums.
Exchange Management shell:
Get-AutodiscoverVirtualDirectory | fl
This shows the correct URL which matches the host name in my SVR record. Ie. servername.domain.com
I put: https://servername.domain.com/Autodiscover/Autodiscover.xml into a browser (externally and internally). After putting in the credentials it shows the expected 600 error.
Please advise of further troubleshooting steps.