I had to reset the ispconfig mysql user. Many services use this user to connect to the database. Is there a list of all of those locations? I found many but I want to make sure I got them all.
The easiets way is: Set the correct password only in the file /usr/local/ispconfig/server/lib/config.inc.php, den download ispconfig, unpack it, go to the install folder and run the update.php script. Choose to reconfigure services during update.