Connection failures fall into three buckets: server, subscription, and network. The app's error banner names the bucket — here's how to interpret each.
server.maintenance / server.unavailable
The specific node is offline. Try a different server in the same city, or let the suggested-server picker choose for you.
server.tier_mismatch
Your plan doesn't include that tier. Either pick a Tier 1 server (available on every plan) or upgrade to Pro for higher tiers.
plan.inactive / sub.expired
Your subscription needs attention. Open Account → Subscription and check the status — past_due usually means update your card, expired means start a new plan.
network.error / timeout.error
Your device couldn't reach the server. Switch from Wi-Fi to mobile data (or vice versa), then try again. Some hotel and corporate networks block UDP — the app will fall back to TCP automatically, but it takes a few seconds longer.