This type of long text when the player is connected to a server. Why is that? Here's the problem: https://pastebin.com/q6quc4zG
It appears you have a NullPointerException, that means that a variable has no value assigned to it (it is null), and you attempted to use it in your code at line 298. Depending on your code, you can use a try/catch or a if statement to get rid of the error.