Block Outlook from trying O365 by Default
[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover]
“ExcludeExplicitO365Endpoint”=dword:00000001
[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover]
“ExcludeExplicitO365Endpoint”=dword:00000001