i install qmail and spamassassin on a new server, i tested the mail function and i work perfectly. The problem is that when is change the setting in tcp.smtp and scan all email with spamassassin i get a message "451 unable to exec qq (#4.3.0)". i have increace the memory limit to 50m and the problem is still the same. Any one know what can couse this error?

qmail crapping on you again? check whether the file /var/qmail/bin/qmail-scanner-queue.pl exists.

the problem with qmail is that even if you managed to get it to work, you do not understand why it worked. i'd wager that you don't. i've learnt that and use postfix instead ever since. clear documentation, clean architecture, i understand the how it works. and more importantly, less headache.

i am not using qmail-scanner, does spamassassin need qmail-scanner to work properly with qmail?

I will like to try other mail system but the problem is that my company only use qmail because some of the web appllication that we develop have function tied to qmail.

can't help you with qmail. learned my lesson long time ago. sorry.

too bad your problem got worse. i wish i can help you with a practical solution that is to change your MTA.