Deactivating Autodiscover for Microsoft 365 in Outlook
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This article explains how you can deactivate Autodiscover for Microsoft 365 in the Outlook registry. This is necessary, for example, if you use a hosted Exchange mailbox at IONOS, or your own local Exchange server. This will prevent Outlook from always trying to log in to the domain that is registered in Microsoft 365.
To customize the Microsoft Windows registry, complete the following:
In the search box located in the taskbar, type regedit and press Enter.
In the registry editor, select the following key in the navigation bar on the left: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Autodiscover
Right-click on the key.
Click on New > DWORD value (32-bit). The DWORD value is created.
Name the DWORD value as follows: ExcludeExplicitO365Endpoint
Double-click on the newly created DWORD value. The Edit DWORD value (32-bit) window opens.
Enter the value 1 in the Value field and click OK.
Create another DWORD value (32-bit).
Name the DWORD value as follows: ExcludeHttpsRootDomain
Double-click on the newly created DWORD value.
Enter the value 1 in the Value field and click OK.
Close Outlook and then open the software again.
If you have already set up a profile and possibly an email account, you must then set this up again.
The autodiscover function for Microsoft 365 is now deactivated.
Please Note
If you have already used the email address of your Microsoft Exchange email account to register for Microsoft 365, we recommend that you change this email address. If the email addresses are identical, the setup may fail due to conflicts.