Server stoping randomly

Hello there,
I've been playing for several day with my Gf and her sister plus some friends. The server feelz good but sometimes it just stop working. One time it's a "time out" error, sometimes a Java exception one, etc. It's different every time. So we have to restart the server everytime and it's really annoying when we have a 10/20 minutes queue.

Here's the log if it could help : https://mclo.gs/depW2a6

Thanks for the help.

I first I though it might work better but we just got a java exception error again. (https://mclo.gs/TuygGVC)

Thanks for answering.