Microsoft Remote Connectivity Analyzer a very good tool to test connectivity and mail flow.
Outlook Connectivity Test
If Connectivity test failed, you need to Expand All and figure out the error and then fix it, for this case, it’s Testing HTTP Authentication Method test failed, Run follow cmdlet to verify and change settings.
Get-OutlookAnywhere | FT Identity,*auth* -AutoSize
Set-OutlookAnywhere -Identity "GDXEX02\rpc (Default Web Site)" -IISAuthenticationMethods Basic
You may need to reboot Exchange servers
To be continue……
Hope you enjoy this post.