Read the reason line, not the headline
A failed join shows Failed to connect to the server at the top and the actual reason underneath. In the server list, an entry that will not answer reads Can't connect to server, one whose name does not look up reads Can't resolve hostname, and one on another version reads Incompatible version!. Those strings are the game's own, from the 26.3 server's English language file. The tables below go by the reason line.
Two server settings come up again and again. The Minecraft Wiki's server.properties page documents server-port, default 25565, as "the TCP port number the server listens on", which "must be forwarded if the server is hosted in a network using NAT". It recommends leaving server-ip empty, so the server "listens on all available IP addresses".
The server cannot be reached
These come from Java's networking rather than from Minecraft, so their definitions are Oracle's, from the Java SE documentation.
| Reason line | What it means | What to do |
|---|---|---|
| Can't resolve hostname, or Unknown host | The name typed could not be turned into an address. Oracle's UnknownHostException is "thrown to indicate that the IP address of a host could not be determined". | Check the spelling. If the server has a domain name, check that its DNS record points at the server. Try the IP address instead to tell the two apart. |
| Connection refused | Something answered at that address and said no. Oracle's ConnectException says "typically, the connection was refused remotely (e.g., no process is listening on the remote address/port)". | Check that the server is running and finished starting, and that the port typed after the colon is the one in server-port. |
| No route to host | Oracle's NoRouteToHostException: "the remote host cannot be reached because of an intervening firewall, or if an intermediate router is down". | Check the firewall on the server machine and on the player's network. |
| Timed out | The wiki's Server page: "The client has lost connection to the server, likely due to disconnecting from the internet or having Minecraft features blocked by a firewall." | For a home server, check the port forward for server-port. See the port forwarding guide. |
The server answered and said no
| Message | Cause | Fix |
|---|---|---|
| You are not white-listed on this server! | The whitelist is on and the player is not on it. Since 26.3, white-list is true by default, so a brand-new server turns away everyone not listed. | Run /whitelist add <name>, or set white-list=false and restart. Operators always get in on Java Edition. See the whitelist, op and ban commands guide. |
| Incompatible client! Please use <version> | The player's game and the server are on different versions. In 26.3 the same text covers both directions, an older client and an older server. | Start the version named in the message from the launcher, or update the server to match the players. |
| Failed to verify username! | With online-mode=true, the default, the server checks every player against Minecraft's account services, and this check failed. | Restart the game and the launcher. If the screen reads Authentication servers are down. Please try again later. Sorry! or The authentication servers are currently not reachable. Please try again., the account service is the problem, so wait and retry. |
| Invalid session (Try restarting your game and the launcher) | The player's login session is no longer valid. | Do what it says: restart the game and the launcher, signing in again if asked. |
| Bad login | The wiki: "The client is running in offline mode and can't connect to an authenticated server." | Sign in to the launcher and start the game online. |
| The server is full! | The server already has max-players on it, default 20. | Wait for a slot, or raise max-players. Operators with bypassesPlayerLimit in ops.json can join a full server. |
| You are banned from this server, or You have been IP banned from this server; when joining, You are banned from this server. Reason: …, or Your IP address is banned from this server. Reason: … | The account, or the address it connects from, is on the server's ban list. The short messages come when a ban lands during play, and the longer ones, with the reason and any end date, when a banned player tries to join. | An operator runs /pardon <name> or /pardon-ip <address>. |
| Expired profile public key. Check that your system time is synchronized, and try restarting your game. | With enforce-secure-profile=true, the default, the server only allows "players with a Mojang-signed public key". | Sync the player's clock, then restart their game. |
| Multiplayer is disabled. Please check your Microsoft account settings. | The player's Microsoft account does not allow multiplayer. | Change it in that account's settings. Nothing on the server fixes this. |
| Server requires accepting the Code of Conduct | The server has enable-code-of-conduct=true, which shows players a code of conduct from the server's codeofconduct folder. | Join again and accept it, or the server owner turns the setting off. |
| This server does not accept transfers | Another server tried to transfer the player here, and accepts-transfers is false, the default, so "incoming transfers are rejected, and the player is disconnected". | Connect to the server directly, or set accepts-transfers=true if transfers are wanted. |
One setting deserves a warning. Turning online-mode off makes "Failed to verify username!" go away, but the wiki says it "should only be set to false when the server is not connected to the Internet", because "hackers with fake accounts can connect if this is set to false". Fix the sign-in instead.
Kicked after joining
| Message | Cause | Fix |
|---|---|---|
| Timed out, End of stream, or Connection Lost | The link dropped. The wiki defines End of Stream as "the server has stopped sending data to the client". | If it happens to everyone at once, look at the server's console for a crash or a stall. If it is one player, look at their connection. |
| Internal Server Error | The wiki: "The server generated an exception when handling the client's request." On a modded server, "this usually happens when a client with an outdated mod tries to join the server with the updated mod." | Read the server log at the moment of the kick, and match mod versions between the players and the server. |
| You have been idle for too long! | player-idle-timeout is set: the minutes a player may idle before being kicked. The default, 0, never kicks. | Raise it or set it back to 0. |
| Kicked for spamming | The wiki: "The client is sending chat messages too quickly." | Slow down, or check a chat mod or macro. |
| Kicked for exceeding packet rate limit | rate-limit is set: "the maximum amount of packets a player can send before getting kicked". The default, 0, disables it. | Raise it, or set it back to 0. |
| Flying is not enabled on this server | With allow-flight=false, the default, "players in air for at least 5 seconds get kicked" in Survival, usually because of a flight mod. | Remove the mod, or set allow-flight=true if the server allows flying. |
| You logged in from another location | The wiki: another client has logged in to the server with the player's username. | Close the other session. If nobody else should have the account, change its password. |
| Kicked by an operator, or Server closed | An operator used /kick, or the server was stopped. | Ask the server's operators. |
Changes to server.properties take effect after the server restarts. The server.properties reference covers every key in the file.
Where ForgeWorld Gaming fits
On a ForgeWorld Gaming Minecraft server, the Address box on the control panel's Console tab shows the address and port players type. The port is not always 25565, so type both, with a colon between them. Each start writes server-ip, server-port, query.port and max-players into server.properties, so those four follow the panel and your plan's player count. Every other key, white-list and online-mode included, is yours to change on the Files tab, followed by a restart. A new Vanilla or Paper server installs the newest Minecraft release unless you pick another version, which is 26.3 today, and we checked that both the 26.3 vanilla server and Paper's 26.3 build write white-list=true into a new server.properties. So the first friend to join will see "You are not white-listed on this server!" until you type whitelist add <name> in the Console for each of them. Last checked 2026-10-18.
Prefer renting to keeping your own server machine online? ForgeWorld Gaming currently offers Minecraft Paper Standard: 8, 16, 24, 32, 40, 48, 56 player slots at CA$9.89–CA$65.99/month. Hosted in Iowa, United States. Prices are in Canadian dollars, with no setup fee and cancel any time. Your server is set up automatically after payment. Continue to secure billing, Minecraft · Paper, CA$9.89 / month (Standard, 8 slots), or compare Minecraft Paper plans.