This is a common error that you may receive when you try to join your server.
How to Fix
Usually, this error is solved by:
- Logging out your Minecraft Account through your launcher.
- Logging back into your Minecraft Account through your launcher.
Running a Pirate Edition of the Game
If you receive this error it could mean that you are using a pirate version to join and you need to enable Offline Mode.
To allow non-premium players to join the server follow these steps:
- Go to your multicraft server from the panel (mc.ggservers.com)
- Click on Files
- Click on Config Files
- Click on Server Settings
- Set “Online Mode” to disabled
- Click Save
- Restart your server