Server Spam Issue

My server was spam with this error every second. Does anyone know what’s the problem going on here and how should I deal with this situation? Thank you.

Techguns is throwing a null pointer exception, which is a bug thatis catchablenon their side likely.
Sponge is catching that exception and reporting it in order to prevent the server from totally crashing. That being said, such a bug should be reported to the mod / plug-in author of techguns so that they can fix it.

OK, thank you so much!

I tried to remove the Techguns mod but still it has another error spam every second. Do you know how to solve it?
PS: The server I have played around one month. All errors just happen today. It doesn’t come with any errors before today.