Kindly keep in mind this happens if your internet is slow / your internet explorer have catch password of a different account.
Just open ie – internet explorer and login to
https://login.microsoftonline.com provied the user id and password , go to outlook and see your mail.
you can sign out and try to close outlook and open again.
now you will be access all your latest mail in outlook and need password in outlook will go away and will show now its conected.