I accidently stumbled on this posting and I am and have been on Newshosting for decades. I remembered something and that is that on your Newshosting account Dashboard you have to place a checkmark in the Request Posting Privileges or some such item name and Save.
I found that weird at the time, but I wouldn’t be surprised if said box still has to be ticked for posting, so please check it out. Again, not in your Usenapp Preferences, but online in your Newshosting account.
There’s no posting problem with the servers, I just posted a couple of large binaries and they went through just beautifully.
Good luck and have fun, Hermie