Several days ago I couldn\'t access the admin panel on my site based on prestashop platform. After entering login and password, I was redirected to login page again and ever
There are some possible things that could have happened to prevent your old passwords from working. One could be that your _COOKIE_KEY_ changed.
You can try to use the following script to generate a new password hash. You can then replace it in the database in the xxxx_employee table (where xxxx_ is your table prefix). I hope that works for you. In any case: keep a backup of your old hashes.
Here is the small script:
Don't forget to remove the script from your server once your done!