Ssh login kills switch and server

Hello everyone,

I am a tech enthusiast and I happen to use linux based operating systems and freebsd a lot. So for me and my friends I setup a linux based server running ubuntu on a ryzen R7 1700 for TeamSpeak, Minecraft, CS:GO … etc. And it worked fine for a long time. Before that we had a server on the Xeon E3-1225 which ran for years without a problem running fedora linux. After I build the ryzen based server I had stability issues. Sometimes when I ssh login to the machine from the outside of my LAN the server crashed. The logs just stopped and even the switch stopped working. The same switch I used for years already. So I installed a mainline kernel because I thought Ubuntu 16.04 is just too old for ryzen. Still crashing so I switched to Arch. Still crashing so I switched the whole machine to an i5-7500 based platform. Still crashing. So I thought ok, maybe it’s because of my MacBook Pro running High Sierra I use to ssh into it. I started using putty on windows. Still crashing. What is killing my server and my switch on ssh login?! I am confused and I need help …

kind regards, tytan