Comment by rsync
Did the error condition actually call out "VPN use" ? Did the HBO UI actually call out, by that term, a VPN ?
... or were you simply using a VPN and that's the most likely culprit for a general failure of the service ?
Genuinely curious ...
Having it spelled out as "Are you on a VPN?" on streaming services is pretty common these days. I guess with the popularity of consumer VPNs that term isn't just a technical one any more.