We are having a similar issue, where we cannot edit/add/delete users.  We have been advised by chat/call support that this is a "known" issue.  The system is supposed to prompt for password, but the window does not pop-up and interface is unresponsive.  

We have attempted different users and browser configurations to no avail.  

An employee has been terminated and we cannot of remove the user account.  We have been advised to wait 5-7 days to have this user removed. 

This user continues to have full privileges and could cause great damage if disgruntled.  We cannot edit rights, modify login, or delete.

Given the sensitive nature of situation, it's unacceptable to have to wait DAY(s).

Alex