So i have a Server made from a R7 5700G on a Asus Tuf B550-Plus Gaming (random parts i got).

Story: I got 2 2tb Nvmes i wanted to add, so i turned off the Node, put them in, turned it on - aaaand couldnt connect, played around more - it was caused by the NVMe I put behind the Chipset. Some noob-like troubleshooting later - i found that the interface just was down - and was confused why i could just take the link up via cli but it didnt by itself - then i saw the name in /etc/network/interfaces was different to the Lan interface the Server now got - so changed that (in this case from enp4s0 to enp8s0) and it worked. A 1min fix that took me way too long to find.

After all that - it does make sense, but I thaught I leave it here in case another not so skilled Person like me comes across it.

Im waiting for the hunderets of comments that say like - its clear blah blah - i just didnt know and also couldnt find anything online.