[CentOS] A gmane mystery

I've been collecting redhat.fedora from gmane for several years, but about a week ago I found that while I could read gmane newsgroups I was unable to post to them - that is, my posts did not appear.

I was able to post to gmane.test, and could read these posts. So I assume there is no problem with my From: or other headers.

I take it that the gmane.linux.centos.general is in fact "mirroring" the mailman mailing list http://lists.centos.org/mailman/listinfo/centos Assuming this is so, I don't know whether the problem lies with the list or with the newsgroup? I seem to be properly subscribed to the mailing list, with my current email address.

Any enlightenment or advice gratefully received.