Keep running into this issue at client sites where an on-premise Microsoft Exchange Server (especially from Microsoft SBS Server) to Office 365 migration has taken place. Client workstations are unable to connect to Office 365 servers via Autodiscover for their migrated email accounts. During Outlook first run it would pre-populate their email correctly but then try to connect to the old email server instead. If the DNS settings for the workstation were changed to non-domain external DNS servers then the email would not pre-populate but the setup would complete successfully. Checked the Autodiscover URL using NSLOOKUP to the Microsoft servers from local domain DNS servers successfully, so felt a little stumpled. Research pointed to the Service Connection Point (SCP) object in Active Directory which can be either deleted from the server or excluded on a per workstation basis, so both will be shown here. Starting with the server first:

Deleting SCP from Server after Office 365 Migration

• Login to a server with Active Directory Domain Services installed as administrator
• Launch ADSIedit from the Start Menu
• Right click on the root of the console and choose “Connect to…”
• Under “Select a well know Naming Context” choose Configuration
• Navigate down through the tree as follows (these are always listed from the bottom up on other tech sites for some reason):
  

  CN=Autodiscover,CN=Protocols,CN=,CN=Servers,CN=Exchange Administrative Group,CN=Administrative Groups,CN=First Organization,CN=Microsoft Exchange,CN=Services

• Delete the entire CN=Autodiscover object if you no longer have any on-premise Exchange Servers
• Reboot the workstation to clear the DNS / AD cache and try to connect to Office 365 servers again

Deleting SCP from Workstation after Office 365 Migration

• Lauch Regedit from the Start Menu
• Navigate to the following key based on your version (16.0 for Office 2016):
  

  HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook\AutoDiscover

• Add a 32-bit DWORD called ExcludeScpLookup with the value of 1 to enable
• Next navigate to the following key based on your version (16.0 for Office 2016):
  

  HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\x.0\Outlook\AutoDiscover

• Add a 32-bit DWORD called ExcludeScpLookup with the value of 1 to enable
• Reboot the workstation to effect the Registry changes and try to connect to Office 365 servers again

If your organization needs any help with troubleshooting issues with Office 365 or with migrating from on-premise Microsoft Exchange Server, then don’t hesitate to contact us for support.