Bananapi M1 disconnecting Ethernet after random amount of time

I got a bananapi M1, Armbian installed, everything works and connection is fine. But when left alone for a while, sometimes after a couple hours, sometimes after 3 days, it disconnects from the Ethernet.

Can’t find it in my router, can’t SSH, and lights stop blinking. When connecting via HDMI to the banana pi, it just shows “ethernet disconnected”, but nothing really wrong or happening.

Power supply is 5V 3A, which should be plenty. No externals connected when this happens.

I haven’t been able to find any fix, or wouldn’t even know where to look.

Pretty new to anything to do with programming or SBCs.