[SOLVED] Weird Mail Problem

[chicomarx]

Hello

I upgraded recently to squeeze.
IspCP was not working anymore so i reinstalled on previous install and replaced my users, and replaced the db.
Everything looks to work normal, except postfix.
I can send messages but not receive anymore.
I always have 554 554 5.7.1 Relay access denied.
I tried everything, i can't see any setting that is not right

Is there a tool that can debug it ? Or do you have any idea what could be wrong?

thx to all for any answer