Exchange Autodiscover not working 403, but can open Externally

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Recently I've set up Exchange Server 2016, configured external DNS accrodingly. Server itself works fine, can send and receive emails. OWA is working fine aswell (externally and internally).

Issue is that Autodiscover is not working properly. I can open it externally via https://example.com/autodiscover/autodiscover.xml (it prompts for user and password), but cant set up an account in Outlook.

When testing with MS Connectivity analyzer it returns that it cannot validate certificate, which is fine since I dont have one and as far as Im cocerned it should work without it. What bothers me is this error:
The Autodiscover service couldn't be contacted successfully by any method.

What could be the cause and solution to this problem?

Best Answer

The most reason why you got a invalid SSL certificate during auto discover is the following:

  • The ssl certificate you are using is selfsigned and not trusted externally
  • You are doing any http redirections and one from the servers isn´t part from the SSL certificate
  • Your Exchange AutoDiscovery configuration points to the wrong URL (you can check that for example via "Get-WebServicesVirtualDirectory | FL")
  • ...

For more info's / Help we need a dump from the MS Connectivity analyzer.

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