Thanks for the link, bubster. That is the same link I had tried before, but I just re-sent a similar message.
I didn't know about 'INDEx', so I'll try that if the current message doesn't arrive.
The problem does seem related to VPN protocol or server location, so perhaps this will be encountered by others. I had set protocol to OpenVPN TCP/IP because I thought that it would afford better stability than UDP. It did work briefly, but started halting at the screen that I described when simply going to URL: sanet.st.
Someone with knowledge of the system software may be able to trace the message to a known cause.
Anyway, thanks for getting back about this. It's probably something simple, but the error screen looks rather ominous. :-)