Authentication Problem with Postgres

Hi all,

sometimes i have a curios problem with my Zope.
Without any errors in any logs Zope could not authenticate himself with
postgres.
The error message is that there is a wrong password.
After a restart of Zope everything works fine until the eror occurs
again.

My sysop has traced the protcols before and after the error.
Zope sends some data and then a crypted password with the salt.
If the error is occured the password that Zope sends is crypted wrong.
After a restart of Zope the password is right crypted.

Could anybody help or explain me this problem, it is very important for
the further use of Zope
for our websites.

Thanks as