So I discovered Chivanet does not allow posting. I was wondering why the fuck nobody was replying to me.
I decided to switch over to eternal-september and it works fine. As an aside, watch out for using eternal-september in Thunderbird because it refuses to login and you get stuck with just the eternal september groups and not the wider usenet (which you can only access with an account while logged in).
Fucking Thunderbird's newsgroup reader has so many problems. Pan seems superior with a tighter experience, though a bit spartan. At least I can FORCE IT TO USE A FUCKING LOGIN CREDENTIAL.