When Migrating to Office 365 you need to reconfigure your Outlook profile.
You need to change your internal and external Autodiscover DNS setting.
Most of the time, this doesn’t work for the internal users, because Outlook is hard-coded to query an AD Service Connection Point (SCP) to locate a server with the Autodiscover service
When this fails Outlook falls back to the next DNS based methods or uses a local XML file.
This XML file is located in the AutoDiscoverServiceInternalUri
Check the AutoDiscoverServiceInternalUri
Get-ClientAccessServer |select AutoDiscoverServiceInternalUri
Solution 1 Powershell
The easiest way to change this is using Powershell to change the AutoDiscoverServiceInternalUri to NULL:
Set-ClientAccessServer –Identity SERVERNAME -AutoDiscoverServiceInternalUri $null
Solution 2 Adsi Edit
If the above method can no longer be used you can use ADSIEdit to remove the SCP manually.
The full path of the SCP is:
CN=ServerName,CN=Autodiscover,CN=Protocols,CN=ServerName,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=OrganizationName,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=DomainName,DC=Suffix
Testing the installation
Use the https://testconnectivity.microsoft.com/ to test the Autodiscover settings: