Here are some Registry Hacks to help with an environment that had an exchange server. When you are having Auto discovery issues Got most from Sherweb.


Registry Hacks for Hosted Exchange

To summarize, we added 4 Dwords in your Registry all of them with a value of 1,
the first one under:

HKEY_CURRENT_USER > Software > Microsoft > Office > 16.0 > Outlook > Setup

Named: DisableOffice365SimplifiedAccountCreation

The other 3 under: HKEY_CURRENT_USER > Software > Microsoft > Office > 16.0 > Outlook > AutoDiscover

Named:
ExcludeExplicitO365Endpoint
ExcludeHttpsAutoDiscoverDomain
ExcludeHttpsRootDomain