I have deleted my previous post, as it was pointed out to me by a good friend that my recommendation suggested I was ignorant that nntp was a protocol just like the more ones that I'm familiar with.
I did realise that but didn't think that through deeply enough. In particular, I was ignorant of its purpose and implementation.
However I do recall many years ago
some ISPs blocking usenet feeds. AIUI for the same reason as parental controls were introduced.
Might it be possible that when they inexplicably set parental filters on your connection they also set up a similar block on nntp access?
My broadband basic info/help site - www.robertos.me.uk.
Domains, sites and mail hosting - Tsohost
Connections: OnePlus 8 Pro max 165Mbps down, 24Mbps up on Three, and B311 4G, tbb tests normally 35-45Mpbs down, 65Mbps off-peak, 9-24 up.
To argue with mindless bigots is foolish.