pop3 proxy and smtp proxy, smtp not working

Hi I'm using at my work 7.2 as a ADSL-router box with proxy between Internet and LAN. I have squid running, and for e-mail I use pop3 proxy and smtp proxy. The squid and pop3 works okay, but for some reason the smtp does not. (can't send e-mails, but reading is working perfectly). Firewall does not give any "errors", nor does the smtp with -d (debug) option. Window$ outlook gives error something like "error code 0x8xxxxxx".. very informative :-( I don't have access to the system now (home), sorry for this little piece of information. Any succestions where to look for?