Drupal "Access denied" you are not authorized to access this page

Problem:

After you login to your Drupal site you immediately see the message "you are not authorized to access this page" or "Access Denied: you are not authorized to access this page"

You can't even access the admin menus. You get this error with the Drupal admin account (i.e. the Drupal main account) or any other Drupal user account.

This problem can happen with any version of Drupal....

Solution:

Your Drupal "sessions" table needs to be repaired. You can repair this table with any mysql admin tool (phpmyadmin, navicat, the free tool from mysql ....etc...).