We have a Unity Connections Server version 8.6.2a talking to Exchange 2010 SP1. We have verified Authenications, HTTPS, Certs etc. If we run a test from the Edit Unified Messaging Screen, we get the following:
Severity Issue Recommendation Details
The validation results for unified messaging service Exchange are the following: Service "Exchange": AuthenticationMode=[Basic] [use HTTPS/validate] Server=[server.internaldomain.com] Type=[Exchange 2007/2010] Username=[domain\UnityUser]
The server domain name can be resolved.
Server server.domain.com can be contacted by pinging.
The service port for calendaring is functioning.
The certificate verification results from SSL is X509_V_OK.
This test does not test all aspects of the configuration of the service. To complete testing, add a unified messaging account for a user and test the account using the Test button on the Edit Unified Messaging Account page.
However under the user we get:
The validation results for the user unified messaging service account email@example.com with service Exchange are the following: Service "Exchange": AuthenticationMode=Basic [use HTTPS/validate] Server=[server.internaldomain.com] Type=[Exchange 2007/2010] Username=[domain\UnityUser]
Failed accessing firstname.lastname@example.org on server.internaldomain.com . Diagnostic= Verb= url= request= response=
The system failed to perform a typical calendar operation. Refer to other warnings and errors generated by the tool, and check the Tomcat log file for details. The system failed while trying to make an API call.
I'm completely at a loss.
My bet is that when you are able to view the Tomcat logs from Unity Connection you will find that you are getting an error 401 response from Exchange.
We ran into the exact same issue with our Unity Connection 8.6.2a system connecting with our Exchange 2010 SP1 server. After working with TAC and Microsoft we were able to get this working by recreating the EWS virtual directory in IIS on the the Exchange 2010 CAS server.
I hope that helps.