Hello!
Interestingly, with psiphon.ca not loading the other day, I tried a few things:
I have NextDNS installed, but with it on or off, in Maxthon, couldn't access the website.
Worked ok, on or off in Edge.
I also have Cloudflare WARP installed (they're a one or the other with NextDNS) & that was off, but after turning on, I could then access the website...
More interestingly, after then turning that off & NextDNS back on, Maxthon could still access the website!
I have Maxthon's Secure DNS setting disabled as these 2 offer far better protection options.