Can't log on to the admin panel after upgrade

[julnil]

Hi, we upgraded to the newest version now, and it seems that my user name is no longer recognized when i try to log in to the admin panel. I had the credentials saved and written down, but the user name is not recognized. Is it possible to get a new? Did something go wrong in the upgrade? 

[bfarber]

What version did you upgrade from? If it was 3.x, note that only usernames or display names could be retained, so if you retained display names you would need to enter that into the login form (instead of your old username).

Also, verify if the login form is asking for "Email Address", "Display Name" or "Email address or display name". It's possible your login handler is requiring an email address to login presently, although you would be able to adjust this after logging in if so.

[julnil]

Thank you. I tried using user name instead of e-mail address as before, and was able to log in now. 

[tlw1999]

The same thing happened to me but it was a different issue. Posting the solution (given to me by the support team) in here for anyone else who may experience the same issue.

After upgrade a lot of my users (including myself) were locked out and passwords were not accepted even though they were correct. It turned out long standing users who had been using the same password could not get in, but newer users or people who had reset their passwords at some point were fine. 

The issue was the older passwords used a different encryption that was compatible with v4. 

The solution is to reset your password before the upgrade and to let your users know to do the same.