Mail net getting to queues

I have rt3 up and running, but users are unable to reply to emails. Outbound mail is working fine.
Sendmail reports the emails having the following error:
Oct 21 17:36:59 rt sendmail[3081]: h9LLawow003080: to="|/opt/rt3/bin/rt-mailgate --queue general --action correspond
–url http://rt.nubridges.com/", ctladdr=rt@rt.nubridges.com (8/0), delay=00:00:01, xdelay=00:00:01, mailer=prog,
pri=31007, dsn=5.3.0, stat=unknown mailer error 255
Software Versions:
RedHat 9.0
mysql Ver 11.18 Distrib 3.23.56
Perl, v5.8.0
Apache/2.0.40
Some things I have tried to fix the issue:
verfiy the link from /etc/smrsh/rt-mailgate to /opt/rt3/bin/rt-mailgate
I am able to send a mail to root@rt.nubridges.com.
I have verified that the version of MIME::Tools I am running is 5.411
I have used lsof to verfiy that rt-mailgate is being called by sendmail, and it is.