Setting up a server is quite easy. All you have to do is create a server, press start, then get the server address to join. However, it’s sometimes not as simple, and you may encounter an error when joining the server. There can be a variety of reasons why an error message can show, and each message has its own ways to solve them.

Some errors show up more often than others, so we will go over some of these common connection errors and how they can be resolved. To help with identifying what kind of connection error you have, I have split these up into basic errors and modded server errors.

Basic Connection Errors

These error messages are most likely to appear on all types of Minecraft servers. Whether the server is vanilla or modded, these error messages can appear, and are usually the easiest to fix.

Unknown Host

Let’s imagine you have instructions to meet with friends somewhere. They give you the address for the location, and you try to get there. However, once you arrive, it turns out there isn’t actually a building there. Simply put, the server does not exist.

If you encounter this error, try the following:

  • Check for spelling errors
  • Check for any spaces before or after the address
  • Verify if the address has changed

Pay close attention to the server address! On the top-left is the correct address. Top-right has an extra space before the address, bottom-left has an extra space after the address, and bottom-right has a spelling error.

Connection timed out: getsockopt

Okay, so we checked the address and it turns out we went down the wrong street. We correct this and find the right building. Now we have a new problem: this is the right place, but the shutters are down with a little “Closed” sign. This message means there is a server here, but it could not be reached.

This error is similar to Unknown Host, but there are a few more things to try:

  • Make sure the server is running.
  • Check for spelling errors with the server address.
  • Verify that the server has not stopped due to a crash.
  • Try using the IP Address. If the Friendly Address says Pending or the server is less than 24 hours old, the Friendly Address may not work for all users.

The getsockopt error means we have found a server, but it could not be contacted. Some reasons for this error could be the server not running just yet, or the server crashed.

Authentication servers are currently down

Minecraft will verify if your account is legitimate and let you securely join a server. It will check your account information and check it against the Authentication server. However, if there was an error connecting to this server, you won’t be able to join online.

You may be quick to think that the Authentication Server is related to your server. The good news is that it’s not your server that has a problem. However, the problem could still be just as tricky. The Authentication Servers are a part of Mojang’s systems, and they are required to securely connect to servers. If there is a connection error here, you can still play the game, but not online.

While we could be logged into the launcher, the game may not have been able to verify the login with the authentication servers.

Here are some ways to help with this error:

  • Log out and then back into the launcher
  • Check if Minecraft is experiencing down time

If the authentication servers are online, this error may appear if there was a communication error. For older versions of Minecraft, the Java version may be outdated, or the server must run offline.

Connection Timed Out

Unlike the earlier getsockopt error, this more generic error message simply means the client was unable to communicate with the server in a timely fashion. You may have everything all ready to go, but you’re just standing there waiting to be let into the building. At some point, you’ll get bored and leave. In this case for the server, the game will abort the connection since it took too long to communicate with the server.

Sometimes, a server connection may fail without a clear reason. Typically, the reason this error can occur is if there was a problem communicating online, or if there is a problem with communicating to the server.

Why might a server terminate a connection if it’s simply taking too long? Well, if it took too long to send and receive messages, the server and other players around you might not have the best time getting the data sent. It may also simply never arrive, so terminating the connection is a way to help with retrying the connection if there was a brief error.

Now, there are a number of reasons this can happen, just as there are a number of ways to troubleshoot the connection. For a detailed list of ways to fix Timed Out, check out this article.

Modded Server Errors

These error messages are most likely to appear when playing on a modded server. While most of these errors can also appear in a vanilla setting, a modded server is most likely to bring these up due to unexpected behaviour. Some messages may also be sourced from the mod loader itself.

Mismatched mods list/channel

Mods add their own particular behaviours to a server. These could be new blocks, new entities, even something bigger like world generation or custom mechanics. With that said, some mods may implement new features in another update. That means if a server has a specific version of a mod, everyone should join with that version, otherwise they risk a registry sync error.

Attempting to join a modded server with the wrong list of mods may trigger this message. In this case, NeoForge has stopped us from joining the server because it found CodeChicken Lib was the wrong version.

While it is easy to set up a server with a modpack, you should be mindful of the version a modpack is on. Each update changes the version of a modpack, and changes can include mod updates, new scripts, or new or removed mods. Because of this, you must make sure that the modpack version on the server matches the client.

Some modpacks may have Better Compatibility Checker installed. This lets users easily know that the version on the client does not match the server. If you see this message when hovering over the red X, update the client.

For custom modpacks, try creating an export of a modpack. Launchers such as Curseforge allow for exporting a modpack from one client to send to every other client. Before sharing a custom modpack, try running a test to make sure that the export has all the files necessary and that the modpack works on a server.

Kicked for flying

Minecraft has a few anti-cheat methods, one of which prevents users from flying. This is done by checking for how long a player has been airborne for and if the player has the required conditions for flight, such as Creative or using an Elytra. Additional methods of flight may not be recognised as valid transport methods and will kick any players for flight. The same applies when falling for too long, such as falling off a floating island over the void.

These types of errors are easy to fix. In the server.properties file is a setting called allow-flight, which can be enabled to prevent being kicked for flight. Once set, if the server detects a flying player, they will not be kicked.

Large Packet errors

Minecraft has a certain limit on how much data can be sent between the client and server. These are called “packets” and are a way to confirm on both sides whether the data is accurate. However, if there is too much data that needs to be sent, the connection is aborted.

For vanilla servers, these errors are not a concern as it’s difficult to create a large enough packet to set this error off. Modded servers, however, can easily cause this error to appear as there is all kinds of data that can be sent or stored. In cases like this, there are mods such as Packet Fixer or XL Packets that can increase the limit and allow for joining without this limit.

Problem Solving the Server

There are many more errors that may show up when connecting to a server, but we have covered some of the basic error messages that may appear so that next time you have players struggling to join, you know how to solve it. If there is a message that you see that you aren’t sure what it means, don’t hesitate to reach out to our friendly Support team!

Don’t let a little error get in your way of starting up a new server! Get started today with one of our cheapest plans and create your new server in just a few clicks!