Error with Postfix/Courier

[OverSpeed301]

Hello,

I have some problems with Postfix and/or Courier :

authdaemond: failed to connect to mysql server (server=localhost, userid=ispconfig): Access denied for user 'ispconfig'@'localhost' (using password: YES)
Aug 28 19:42:25 **** maildrop[16529]: Temporary authentication failure.
Aug 28 19:42:25 **** postfix/pipe[16420]: DDA7929C0F09: to=<web1@zeez.fr>, relay=maildrop, delay=271303, delays=271298/4.1/0/0.06, dsn=4.3.0, status=deferred (temporary failure. Command output: /usr/bin/maildrop: Temporary authentication failure. )

I have checked the MySQL password in all files of Postfix and Courier, it's the good password. I have even written in clear all the passwords and it don't work. Any ideas ? I can't receive any mail and it's a huge problem.

Cordially,
OverSpeed301.