I brought this to the attention of my hosting provider and they said that it is a Sponge problem, so lets see if you guys can help!
Here is a paste of the crash-report: https://pastebin.com/yrnHpwpU
And in the console, I get this:
But this time around, I am getting this after the server restart.
09.10 17:46:06 [Server] INFO Error occurred during initialization of VM
09.10 17:46:06 [Server] INFO java.lang.OutOfMemoryError: unable to create new native thread
09.10 17:46:06 [Multicraft] Server shut down (starting)
09.10 17:46:06 [Multicraft] Not restarting crashed server.