[Mailman-Users] Weird response from a subscriber's mail server

[Christian F Buser]

Hi all 

I have a new problem with our mailing list (Mailman 2.1.23 on cPanel 62.0.17 where a subscriber's provider rejects messages from the list. Not the usual way, where the message simply bounces; here the original sender of the list message receives a notification as shown in the attachment. 

The receiving address is a subscriber of the list for a long time, but these messages started to show up just today. 

What can I do to solve the problem? 

Thank you, Christian 
-- 
Christian F. Buser, Hohle Gasse 6, CH-5507 Mellingen (Switzerland)      
Hilfe fuer Strassenkinder in Ghana: http://www.chance-for-children.org