If you suspect some anti-spam filter that mistakenly filters out your messages you may try to change your name and e-mail address and post a reply.
If that post reaches the server it may really a kind of filter applied on your account.
Google groups has an interface to post to newsgroups, you may try to find it in the new (terrible) google groups site and use it in the meantime.
NTTP server
If you suspect some anti-spam filter that mistakenly filters out your messages you may try to change your name and e-mail address and post a reply.
If that post reaches the server it may really a kind of filter applied on your account.
Google groups has an interface to post to newsgroups, you may try to find it in the new (terrible) google groups site and use it in the meantime.
Good luck!