The mailing list for listmasters using Sympa

[<address@concealed>]

I've recently tried to upgrade to Sympa 6.0.1 from 5.4.7 and have run into a
problem.

Any message I send to our existing lists gets returned as undeliverable and
the following ends up in my mail log

Jan 11 16:28:38 listserv sm-mta[30540]: o0C0SbVh030539: to="| /usr/bin/queue
test@domain name", ctladdr=<test@domain name> (2/0), delay=00:00:01,
xdelay=00:00:00, mailer=prog, pri=30952, dsn=5.0.0, stat=Insufficient
permission

Jan 11 16:28:38 listserv sm-mta[30540]: o0C0SbVh030539: o0C0ScVh030540: DSN:
Insufficient permission

I've checked the permissions on queue and it's set to rwsr-x--x

Suggestions on what else might be causing this?