So, it appears that sometimes, my browser switches protocols, for unknown reasons.
Is there a way to disable this particular check? Otherwise, I suppose that the answer is to have my http server only respond on IPv4, which is a bit annoying but doable… but this behaviour isn’t exactly what I would call mobility friendly…
If you are using Cloudflare though, it’s better to not adjust that setting, and instead set up the trusted proxies. In that case you’d search for ‘Trusted Proxes’ in the dashboard, paste in the two sets of IP addresses here: IP Ranges
and check the headers to be forwarded (I believe you’d check all except the last one)