A TLS packet with unexpected length was received

For the last day or two I have errors updating my flatpaks on Kubuntu 18.04. (I know it’s really old.)

I uninstalled the Firefox flatpak which was saying something about not found and now I’m left with:

$ sudo flatpak update
[sudo] password for bigbird: 
Looking for updates…
error: Error reading data from TLS socket: A TLS packet with unexpected length was received.
bigbird@sananda:~/pq

What’s going on?

I’ll work on the Firefox issue again after this is fixed.

The TLS error goes away when I turn off my VPN (VPN Unlimitted).

Firefox updated once, but now says package not found even though Flatpak says it has an update.