Below is a copy of my debug level logs when I tried to post something to an existing group with my current usenet provider, they say the problem is with NB, and as I was able to post files and requests previously I believe them (I don't post often, so not sure when this stopped working)
[17:18:49] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:18:49] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:18:49] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:18:49] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:18:49] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:18:49] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:18:49] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:18:50] HIGH usenetbucket |340 start posting.
[17:18:50] HIGH usenetbucket |340 start posting.
[17:18:50] HIGH usenetbucket |340 start posting.
[17:18:50] HIGH usenetbucket |340 start posting.
[17:18:50] HIGH usenetbucket |340 start posting.
[17:18:50] HIGH usenetbucket |340 start posting.
[17:18:50] HIGH usenetbucket |340 start posting.
[17:18:51] HIGH usenetbucket None |441 required header missing.
[17:18:55] HIGH usenetbucket None |441 required header missing.
[17:18:55] HIGH usenetbucket None |441 required header missing.
[17:18:56] HIGH usenetbucket None |441 required header missing.
[17:18:56] HIGH usenetbucket None |441 required header missing.
[17:18:56] HIGH usenetbucket None |441 required header missing.
[17:18:56] HIGH usenetbucket None |441 required header missing.
The same thing happens if I post a file (above) or just a message (say, a message saying test, test testy test to a.b.test)
[17:30:42] DEBUG Connection Status: SSL Connection Server: reader.usenetbucket.com SSL Cert: reader.usenetbucket.com Stats: AES128-SHA 128 TLSv1/SSLv3
[17:30:42] HIGH usenetbucket |340 start posting.
[17:30:43] HIGH usenetbucket None |441 required header missing.