Here is an obnoxious one. You move mailboxes from your local Exchange server to Office 365, Outlook connects and sends/receives just fine, but pops up every few minutes asking for password and nothing you give it makes it go away.
The first thing to check is to make sure you don’t have a bad/incorrect password saved in your credentials manager. I’d go in there and delete anything that looks like a Microsoft/Office/Outlook service. If that still doesn’t work, here is the solution we found after weeks of poking around.
Go into the registry, key where “X.0” is your office version: 14.0 = 2010, 15.0 = 2013, 16.0 = 2016, etc…:
and create a DWORD “ExcludeScpLookup” with value 1
No more obnoxiousness
And one more neat trick – if you want to do this domain/server wide, drop this line in your login script (all users can modify their own HKCU key):
reg add HKCU\Software\Microsoft\Office\14.0\Outlook\AutoDiscover /v ExcludeScpLookup /t REG_DWORD /d 0x1 /f