Why every node times out

One node timing out is routine; all of them timing out simultaneously almost always has a shared cause. In descending likelihood:

• Your own connection is down: turn off the system proxy and open any site directly — if the bare network is dead, every test will time out;
• The subscription is dead: plan expired, account suspended, or servers migrated while your copy is stale. Update the subscription in Profiles and check the expiry/quota info on the card;
• Your uplink interferes: some networks (campus, corporate, certain ISPs) block proxy protocol handshakes — symptoms: works at home, all-timeout elsewhere. Try nodes on different protocols/ports from your provider (e.g. ss → trojan);
• System clock is off: several protocols are time-sensitive; a clock drifted beyond tolerance fails every handshake. Check that Windows time sync is on;
• Security software: a firewall or AV blocking the core's outbound connections. Whitelist Clash and retry;
• The test URL itself is blocked: rare, but if the default test endpoint is unreachable on your network, nodes look dead while actually working. Pick a node and browse to verify, or change the test URL in settings.

The golden rule: first confirm "network works without the proxy", then "the subscription is alive" — only then is deeper digging worth it.