First please, make sure that you are trying to connect to your server using the right server IP!
Use IP : PORT (exemple:

Checking if the problem is your server or your computer.

First go to your Multicraft.
You can access it clicking here:
Once you are login, open your server and see if it is stopped or it is running.

If only the “Start” and “Restart” buttons are green, click on the green “Start” button and then try to connect again.

If you are still getting this error, the error is on your computer.
So please try troubleshooting.

I am logged in, my Multicraft shows that the server is running, but even then the error appears.

This error usually happens when your Firewall is not allowing the traffic to your X.X.X.jar file located in C:\Users\user\AppData\Roaming.minecraft\versions\<version>.
(Simply, the version you are trying to use)

To fix this problem, you can temporarily disable your Firewall.

To disable your Firewall go to:

Control Panel
System and Security
Windows Firewall (or just type “Firewall” in your Start Menu Search Box)

Then, on the left, you can Disable the Firewall in “Turn Windows Defender Firewall ON or OFF”.

Once disabled, you can try to join in your server.

We recommend you to turn your Firewall back ON after testing it.
If you leave your Firewall OFF, malicious programs will be able to get access to your whole computer.

If the error isn’t fixed, you can whitelist (allow) your Minecraft to bypass the Firewall.

You will need to allow “Java(TM) Platform SE Binary”

If it's still not working, try and whitelist the Minecraft Jar that you play. For this, you just need to find “Allow another program…” then select your current Minecraft Version.

To find your Minecraft folder, and your current version, go to:


Windows Drive


<Your user>





Click on the Version folder that you play, and whitelist 1.XX.X.jar (exemple: 1.12.2.jar)

If it's still not working, there are many other factors that can cause this.

If you can’t fix the problem, please try using a different Minecraft Version.

Example: If you are playing on 1.12.2, just try to connect with 1.12. If you are playing on 1.8.2, just try to connect with 1.8.8.

Feel free to open a ticket in your Client Area if you need further help.
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