This error can occur when your Minecraft client receives unexpected data from the server. It often happens when a network connection is unstable or interrupted.
To fix this issue, try the following solutions:
1. Restart your Minecraft client and try connecting to the server again.
2. Check your internet connection and make sure it's stable. You may want to reset your router or modem.
3. If the issue persists, try connecting to another Minecraft server to see if the problem is specific to the server you were originally trying to connect to.
4. If none of the above solutions work, try contacting the server administrator to see if there are any known issues on their end.
I hope that helps! Let me know if you have any further questions or issues.