how to see the password for ispconfig user in ispconfig database?
Told you that in post #5?
Think about the config - what interacts with the mysql databases and where are you going to find the files?
In this case I would look in any of the /etc/postfix/mysql-virtual_ files
I would also look in /etc/dovecot/dovecot-sql.conf
Or authlib config files, or even amavisd config files.
Seems like the mysql ispconfig username/password recorded in those files does not match permissions on the actual database itself. Have you manually copied SQL tables from somewhere else?
You could investigate whether or not to set permissions via a SQL "GRANT" statement on the database.
However, you might find the easiest way is to run update_from_tgz.sh and then answer "yes" to reconfigure database permissions.