Outlook blank or Empty authentication window When connected to office 365
After migrating from on-perm to Office 365 on terminal server I get this blank authentication window. the fix I found is to add in the registery this key :
HKCU\SOFTWARE\Microsoft\Office\15.0\Common\Identity\EnableADAL REG_DWORD 0
or
Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity] "EnableADAL"=dword:00000000
There is another case with similar behavior in outlook 2016 or outlook 365 and the fix is this registry key :
Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity] "DisableADALatopWAMOverride"=dword:00000001
After adding this line, Outlook got connected with no issue, yet this is not recommended solution by Microsoft, here is more details on how to over come this error:
Disabling ADAL or WAM to fix Office sign-in or activation issues not recommended – Office 365 | Microsoft LearnGood luck