Almost every "I can’t join" problem is one of a dozen specific errors, and each has a clear cause. Read the exact red text Minecraft shows you - it is more precise than it looks - and jump to the matching section below.
First, the basics that trip everyone up: connect to your address with no port (just yourname.levyathan.ch, not :25565), and make sure you are on the same Minecraft version as the server. On Levyathan, the very first time you join a sleeping server you may be asked to "rejoin in a few seconds" - that is the server waking up; joining again a moment later drops you straight in. That is expected, not an error.
"Connection timed out" / "Took too long to log in"
Your client could not reach the server at all - the request went out and nothing came back. Usual causes, in order of likelihood:
- 1The server is offline or still starting. Check the dashboard; start it and give a modded server a few minutes to boot.
- 2A typo in the address. It must be your exact subdomain, e.g. dragons.levyathan.ch.
- 3Your own network blocks it - some school, work or public Wi-Fi firewalls block game traffic. Try a phone hotspot to rule this out.
- 4If you self-host the server at home instead of on Levyathan, this is usually a missing port-forward of TCP 25565 on the router.
"Failed to verify username" / "Authentication servers are down"
The server tried to confirm your account with Mojang and could not. Either Mojang’s login service is having an outage (check status.mojang.com / the Minecraft status page and wait), or you are signed out - fully quit and reopen the launcher so it refreshes your session. This error is also why a legitimate (non-cracked) copy of the game matters: online-mode servers, which is to say all secure servers, require a real authenticated account.
"Outdated server!" or "Outdated client!"
A version mismatch, and the message tells you which side. "Outdated client" means your game is older than the server - change your launcher profile to the server’s version. "Outdated server" means your game is newer - either select the matching older version in the launcher, or change the server to your version in its settings. They must match exactly: a 1.21.1 client cannot join a 1.21 server.
"io.netty... Connection reset" / "Internal Exception"
The connection was opened but then dropped mid-handshake. It is usually transient - a brief network blip or the server restarting - so try again in a minute. If it is persistent, it often points to an unstable connection on one end, or a mod/plugin on the server throwing errors during join (check the console log right after the attempt).
"You are not white-listed on this server"
Exactly what it says: the server has its whitelist on and your username is not on it. Ask the owner to add you from the Players tab (case does not matter, spelling does). If you ARE the owner, add yourself there, or turn the whitelist off while testing.
Modded: kicked for a mod mismatch
Joining a modded (Fabric/Forge/NeoForge) server requires the same loader and the same mods, at the same versions, on your client. A mismatch shows up as a long disconnect screen listing the offending mods, or a generic "connection closed" during the modded handshake. The reliable fix is to install the exact modpack the server runs using the Modrinth App or Prism Launcher, which match versions for you. Note that client-only mods (minimaps, shaders) do not need to be on the server, and Levyathan deliberately skips installing them server-side.
"Can’t resolve hostname"
Your computer could not turn the address into an IP - almost always a typo in the hostname, or a DNS hiccup. Double-check the spelling, and if it is freshly set up, give DNS a few minutes to propagate. Switching your device’s DNS to a public resolver (1.1.1.1 or 8.8.8.8) resolves the occasional stubborn case.
Still stuck?
Open the server’s Console tab right as you try to join - most real errors print a line there that names the cause. If nothing appears at all, the connection is not reaching the server, which points back to the address, the version, or your network rather than the server itself.