list troubles


Sorry for posting to the list, but I had no clue who to address.

Recently I had some troubles sending emails to the list, for they were bounced
back with this delivery status notification:

The following message to <> was
The reason for the problem:
5.1.0 - Unknown address error 550-'Postmaster verification failed while
checking <prvs=meesters=367897361@...624...>\n(result of earlier
verification reused).\nSeveral RFCs state that you are required to have a
postmaster\nmailbox for each mail domain. This host does not accept
mail\nfrom domains whose servers reject the postmaster address.\nSender
verify failed'

What then follows is my entire mail I was going to send.

Unsubscribing / Re-subscribing helped. matplotlib-users is the only list where
I had such problems, but not the only one using Mailman I'm using.

Could this be a problem with the mailserver I'm using?

My apologies if this is not considered to be of general interest. Please reply
directly to my address in this case.