Different networks, different stacks
A phone on cellular uses a different DNS resolver, IPv6 path, and filtering policy than a desktop on Wi-Fi. A site can fail on one path and succeed on the other. That is not proof of a global outage.
Desktop-only problems
Browser extensions, corporate proxies, stale hosts files, and leftover VPN clients often affect computers and not phones. Try a private window, another browser, and — if you know how — a temporary disconnect from VPN. Do not edit the hosts file unless you understand it; a bad entry will make one site fail forever on that machine.