Access Denied with MySql - Any Host

Hi !

I work with RH7, Mysql 3.23.58 and PHP 4.3.4. Some of my mysql users
are configured with any host. Since this afternoon, I can't connect to
Mysql with an user configured with any host (%) and a password. When I
change password to "no password", I can connect to the server. All
users configured with localhost have a password and work fine, only
users with "any host (%)" don't work.
I work with PhpMyadmin to modify and create users/databases.

I tried to connect via phpmyadmin and via a simple PHP-script.

Dos anyone have an idea ?

Thanks a lot.

Gaëlle