[Mailman-Users] Problem solved: it was the MTA

[Elena Fraboschi]

No, it was not a typo, just an ellipsis :-)

I am very careful when it comes to changing things.  I read
that changes are not to go into Defaults, and I made the
changes in mm_cfg.py.   I just omitted the gory details :-)
(that what I put in mm_cfg.py in the end becomes Defaults).  
But you are right, I should have been more precise.  Best, elena