Server closes itself after hours (Centos 7)

Hey there

I'm currently having some problems running my SA-MP server on my dedicated server. Since yesterday my server closes itself every 12-18 hours without any reasons (no errors in the server log). The load isn't too high since it most likely happens at night when the server is (almost) empty.

I tried to load the server on a few different ways such as screen, nohup and screen + nohup but that did not seem to work out.

Am I doing anything wrong? How could I recreate this problem?

Thanks!