[Mailman-Users] Held Message for "implicit address"

[HarryStyron]

What does "implicit address" mean in the administrative hold message?

I run a series of lists for different groups.  Most of them are set for
subscriber only posting.  At the moment my subscribers are complaining
that all of their traffic is held (and I'm complaining, too!) which it
is, with the above reason in the admin approval message.

USE_ENVELOPE_SENDER=0 was set when Mailman was originally set up.  What
am I missing?

Thanks,

Harry Styron
hlstyron at wcrklaw.com