Proxy server issues

I’ve got the roon front end running on a computer (W10) that I don’t want to be able to automatically connect to the internet. So it connects via a fake proxy server which looks for ‘http://fakeproxy’.
It’s configured to ‘not use the proxy server for local (intranet) addresses’ and the following are in the exception list: [https://api.roonlabs.net;http://sp-pr-fa.audio.tidal.com;http://roonlabs.net;www.roonlabs.net;www.roonlabs.com;https://go.roonlabs.com;https://www.ecosia.org;https://pwa-bob.de7.quickconnect.to;https://account.tidal.com;www.tidal.com;https://community.roonlabs.com]. But when I fire up roon, all the album and track images appear - then disappear. Scrolling the page makes some re-appear and then disappear.
Using a roon core Nucleus, Melco N1 NAS, Meridian 218
Any ideas?