To verify weather modern authentication is configured or not you must check the registry.
Press Windows Key + R to bring up the run menu.
In the open field type Regedit and Click OK
Navigate to
“Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity.”
Check if the DWORD value named “EnableADAL” exists and is set to 1
If the DWORD value does not exist
Add the DWORD value for “EnableADAL” to 1.
Select OK.
Check if the DWORD value named “DisableADALatopWAMOverride” exists and is set to 0.
If the DWORD value does not exist
Add the DWORD value for “DisableADALatopWAMOverride” to 0.
Select OK.
Close Regedit.
Open Outlook and sign-in.
