Someone's restarting my server :/ pls help

Idk how but some hater is restarting my server every 5 mins :/
Idk if it is a program or something.
I checked the permissions - nothing fishy there, checked the ops list, checked the hawkeye log for all comands and stuff - no fishy things.

Please give ideas how to locate and fix the problem and how to catch the hater.
50+ people connect on the 1st 2 mins after the server restarts so... I can not ban everyone of them.

No responses yet.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Try to turn on whitelist and se if the same hapends

You can chance the server.propeties so only one can logg in at once
And se Who is restarting the server

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Firstly, Is your server in Offline mode?
Secondly, Check the console/logs after every restart - If something comes up, post below