Outlook 365 Prompts for but does not accept password

The issue may be that the EnableADAL key is set to 0 and needs to be changed to 1.

1. Go to “Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity.”
2. Verify if there is a DWORD value named “EnableADAL” that is set to 0. (If “EnableADAL” is not found in the registry, skip to step 6.)
3. Update the DWORD value for “EnableADAL” to 1.

Site for reference: https://confluence.som.yale.edu/display/SC/Outlook+Modern+Authentication+Registry+Setting