First thing to note, there are multiple versions of Minecraft and coding is only supported on the main Java edition. The most common problem reported is trying to connect to a server designed for a different version of Minecraft.

How do you know if you have the Java edition? It will say so in the Minecraft launcher and you'll see a "Multiplayer" option in the list:

How to connect

In the CK code editor you'll need to grab your server URL. To do this click on the Server button in the right hand toolbar:

You'll see your unique server URL on this page. You can copy it to your clipboard by clicking the copy button.

Then head over to Minecraft. On the Multiplayer section you'll see a list of servers (yours may be empty). Click the direct connect button and paste/ type your server URL into there. Then connect to your server. It should load within 30 seconds.

Common Fixes for connection errors

If you have the Java edition, the most common fixes for connection troubles are: 

  1. Restart Minecraft - you’ll be surprised how often this works.

  2. If you have a firewall or parental control software enabled, please try disabling these first as these can block the connection to Minecraft.

  3. Double check your URL - it can be easy to make spelling mistakes. Oh, and If you are using the ip address on the PC edition, it updates and changes frequently, so be sure to copy and paste the latest. 

  4. Disable any client mods that may be conflicting with your server. Although we do support some mods, it is hard for us to make sure they all work with our servers and the latest Minecraft version. 

  5. Disable any custom plugins you are using - a bad plugin can cause the server to crash while starting up. 

  6. Hard reboot your server. To do this, click the server icon to see the server page, then press the restart server button. 

Authentication failed/ authentication servers are down/ failed to verify username

This error is suggesting a problem with Minecraft's servers that verify your Minecraft username is correct. Microsoft rarely have these servers go down, but they have been known too. Sometimes Minecraft just gets confused with your logged in state. Here is how you fix this:

  1. Close your game.

  2. Log off your account from your launcher.

  3. You will then be asked to type in your email and password again, please do.

  4. Once logged in, you can then start your game and join the server.

Connecting to World 🗺

The ’connect to world’ bug is actually a really minor issue with Minecraft (sadly it does seem to happen more frequently when the servers start for the first time) and it’s quite easy to fix. If you follow these steps it should work.

Restart Minecraft and check that it is set to the correct version. Open your Code Editor, go to the server page and press ‘Restart Server.’ Once the server is green again, create a new project based off one of our course maps (to prevent any custom changes causing issue). Connect to your server in Minecraft!

Server Crashing When It Starts Up 

This can happen if the map has things which are causing it to crash 💥. This might involve some bad command blocks, or a lot of things happening at once like hundreds of TNT explosions. 💥💥💥

Try a new map by creating a project following one of our courses to confirm it’s fixed. If it works, you might want to change the map you’ve been using to remove command blocks or other unusual things. The code you’ve written might have a bug in it (such as never finishing a while loop), so will crash when you press the Run button. 

To fix this, check your code is written like we suggest in the courses. If you’ve uploaded any plugins, one of them might be causing the server to crash. You can disable any plugins on the project settings page, so work out if that’s the issue. If you’ve tried the steps above to fix any issues, and you’ve waited a couple of minutes for it to boot, you can hard restart it. To do this, click the server icon in the bottom left of the Code Editor. You’ll see the server admin page. Then click the restart button and wait a couple of minutes. 

Command Blocks

We don’t recommend using command blocks as they can cause servers to crash really easily 💥. If something does go wrong, we recommend you restore your world to an earlier version. To restore your world click the World button on the right of the Code Editor - scroll down and click the reset to template button. 😊

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