[Mailman-Users] Re: posts building up in /var/spool/mailman/in

If urllib2.urlopen throws an exception, you need to figure out why. 
Does

wget https://publicsuffix.org/list/public_suffix_list.dat

retrieve the data?

After posting the message to this list I checked if the mailman server could resolve https://publicsuffix.org and it failed thus for our incident it was related to a firewall rule that allowed outbound 443 traffic being revoked which caused the delay in delivering and build up of posts. After the rule was added back the spooled mailman posts in the "in" directory were delivered within minutes.