OpenCPN not connecting to vcharts

[Scorpius]

Hi,
We're having trouble getting any charts to come up on OpenCPN on our second computer. We are having no trouble at all with the first one and, as far as I can see, everything relevant is identical.

The VERY small scale world map appears along with all the tide and current stations, and AIS targets, but no larger scale charts.

We downloaded the oesenc charts for British Columbia. Don't work.

After tearing our hair out for a couple of days I thought, wait, maybe it's a security issue with the computer name or something - so I downloaded the US (NOAA) charts for Washington state which presumably don't have a security layer. Doesn't work!

I'm at my wits end here! Can anybody help?

Thank you very, very much in advance.

PS. It's an HP 15bw007ca computer running fully updated Windows 10.