Minecraft connection errors and what they mean
These are the 11 Minecraft connection errors players see most, what each one means and what to fix first:
| Message | What it means | Fix first |
|---|---|---|
| Connection refused: getsockopt | The computer at that address answered, but no Minecraft server listens on that port | Start the server and check the port |
| Connection timed out: getsockopt | Nothing answered at all | Check the IP, the port forwarding and the firewall |
| Unknown host, Can't resolve hostname | The name in the address does not lead to an IP address | Check the spelling and the domain's DNS records |
| Incompatible client!, Outdated client!, Outdated server! | Your game and the server run different versions | Pick the version the message names in the launcher |
| You are not white-listed on this server! | The whitelist is on and your name is not on it; Paper says whitelisted | Ask an operator to add you |
| Failed to verify username! | The server could not confirm your Minecraft account | Close the game and the launcher, then log in again |
| The server is full! | The max-players limit is reached | Wait for a free slot, or raise max-players |
| You are banned from this server | An operator banned your name or your IP address | Contact the server's staff |
| Internal Exception: io.netty.handler.codec.DecoderException | Your game and the server disagree about the data they send, usually because of different mods | Use exactly the same mods and modpack version |
| This server requires a custom resource pack | You declined the server's resource pack | Set Server Resource Packs to Enabled in the server's entry |
| Server requires accepting the Code of Conduct | The server shows rules you have to accept first | Join again and accept the code of conduct |
The getsockopt at the end of the first two can also read no further information, depending on your system. It names the place in Java where the failure was noticed, not the cause, so read the words before it.
How to fix Connection refused: getsockopt in Minecraft
To fix Connection refused: getsockopt in Minecraft, make sure the server is running and that you use the right port, because the error means the computer at that address answered but nothing listens on that port. Check these in order:
- The server is not running. It crashed, it is still starting, or someone closed the server window. Look at the console or the panel before anything else.
- The port is wrong. A Java server listens on 25565 unless server-port says otherwise. Many hosted servers share an IP address and give each server its own port, so the address needs that port after a colon, such as 203.0.113.10:25570.
- You connect from the server's own computer to its external IP. Use
localhostthere instead.
How to fix Connection timed out: getsockopt
To fix Connection timed out: getsockopt, check the IP address first and then the router and the firewall, because the error means nothing answered at all before the game stopped waiting. On a server at home, these are the usual causes:
- A friend used your internal address, one that starts with 192.168 or 10. It only works inside your own network.
- Your external IP changed. Most home connections get a new one now and then, so last week's address can be dead.
- The router has no port forwarding rule for TCP port 25565, or it points at the wrong computer. Our guide on how to make a Minecraft server shows how to set one up.
- The firewall on the server PC blocks Java, so the router forwards players to a closed door.
- Your provider shares one public IP between many homes, and port forwarding cannot work at all.
On a hosted server the network side is already done, so a timeout usually means a typo in the address or a network on the player's side that blocks game ports, which happens on some school and office networks.
How to fix Unknown host and Can't resolve hostname
To fix Unknown host and Can't resolve hostname in Minecraft, check the spelling of the address first: both mean that the name you typed does not lead to any IP address. Leave out http:// and any spaces, because the address is only the name, or the name, a colon and the port.
If the spelling is right, the domain itself is the problem. It needs an A record that points to the server's IP, or an SRV record for a server on another port, and a record you just added can take a while to reach every network. Our guide to a Minecraft server domain explains both records. Until then, players can join with the IP address and the port.
How to fix Outdated client and Incompatible client errors
To fix an Outdated client or Incompatible client error, play the exact Minecraft version the server runs, which the message names, for example Incompatible client! Please use 26.3. A vanilla server shows that one message whether your game is older or newer. Paper and Spigot say Outdated client! Please use 26.3 when your game is older, and Outdated server! I'm still on 1.21.11 when it is newer than the server. In the Java launcher, open Installations, add a new installation with the server's version and start the game with it.
A server owner can let several versions in at once with ViaVersion, which lets newer clients join an older server, and ViaBackwards for the other way around. Both run on Paper, Fabric and Velocity, with builds up to 26.3. On a crossplay server, keep Geyser up to date as well, because Bedrock players update their game automatically.
You are not white-listed on this server
You are not white-listed on this server! means the whitelist is on and your name is not on it, and since Java 26.3 every new server starts with the whitelist switched on. An operator fixes it with whitelist add and your exact name in the console. Our Minecraft server whitelist guide has every command, the Bedrock allowlist and the Floodgate names of Bedrock players on a crossplay server.
How to fix Failed to verify username
To fix Failed to verify username!, close Minecraft and the launcher completely and log in again, because the error means the server could not confirm your account with Mojang's session servers. If that does not help, one of these is the cause:
- The authentication servers are down. The game then says so in its own message, and waiting is the only fix.
- Multiplayer is switched off for your account, which the game reports as Multiplayer is disabled. Please check your Microsoft account settings. The switch is in the privacy or family settings of the Microsoft account, for example on a child account.
- A launcher without a real account. A server with online-mode=true lets in checked accounts only, so a cracked launcher never gets past this point.
- A proxy that is set up wrong, on the server owner's side. Behind Velocity, the servers need online-mode=false and the same forwarding secret as the proxy, or players cannot log in.
Can't connect to a Minecraft server on the same network
If you can't connect to a Minecraft server on the same network, use its internal address instead of the external one: localhost on the computer that runs the server, and an address such as 192.168.1.20 on any other device at home. Many home routers cannot send a connection out to their own external IP and back in again, so the external address fails from inside your home while it works for friends elsewhere.
Find the internal address with ipconfig on Windows, where it is listed as IPv4 Address, or in your router's list of connected devices. For a world opened to LAN from singleplayer, the game prints the port it chose in the chat.
Can't connect to a Minecraft server but others can
When you can't connect to a Minecraft server but others can, the server is fine and the cause is on your side: your version, your account, your network or your place on the server's lists. Check these:
- Your version differs from what the others play. The server list shows Incompatible version! in that case.
- Your account is not on the whitelist, or is banned, or its session expired.
- Your network blocks the port, which happens at schools and offices, or a VPN gets in the way. A server with prevent-proxy-connections=true kicks players whose network does not match the one Mojang saw at login.
- Your mods differ from the server's, on a modded server.
Bedrock players can't connect to a crossplay server
Bedrock players connect to a crossplay server on its Bedrock port, 19132 by default, over UDP, not on the Java port. In the Bedrock app they add the server under Servers with the same address and that port. A server at home needs a UDP forwarding rule for it, next to the TCP rule for Java. Xbox, PlayStation and Switch players cannot type in a custom server at all, and our guide to a Minecraft console server shows the way around that.
Internal Exception: io.netty DecoderException
Internal Exception: io.netty.handler.codec.DecoderException on a Minecraft server usually means that your game and the server do not run the same mods or the same modpack version, so they disagree about the data they send. Install the exact modpack version the server runs, or compare the mods folders one by one. If everyone gets it after an update, look in the server's log for the mod that failed.