A promoted admin user is unable to login to the Admin Portal

Original Question or Issue:

Environment:

Steps to Reproduce:

Enable Allow Email as Username from the Admin Portal >> Settings >> Admin tab
Create a Full Access user and use the user's email as a username
Promote the newly created user to Admin
Set the Admin Email value to the user's email address from the Admin Portal >> Settings >> Admin tab, and click on Save.
Log in to the Admin Portal using the newly created/promoted user

Error or Log Message:

Invalid username and password

Defect or Enhancement Number:

Cause:

Resolution or Workaround:

If an admin user uses an email as their username, ensure that the Admin Email in the Admin Portal does not use the same email.

Log in to the Admin Portal as working admin user or the default admin account.
Go to Settings >> Admin tab and look for Admin Email.
Change the value to an email that does not match the promoted admin's email/username.

Notes:

Alternatively, you could impose for admin users to not use their email address as their username in FileCloud.