You may be having the issue with the Ethernet port I came across very recently as the temperature and humidity drop in New York City.
I built a large Delta Kossel this summer (1800mm x 700mm frame) out of 2020 and 2040 aluminum with corners of thick aluminum.
My four-pin 0.9 42mm Nema 17 stepper motors are connected to the frame but there is a gap of rubber between the motor and aluminum corner for vibration and noise prevention.
The motors do not have shielded cable and the aluminum isn’t a great conductor for a ground.
During the summer and high humidity, I didn’t notice a problem.
The other day during a 12 hour print, I lost any connectivity with the Ethernet port. Even the indicator light on the gigabit switch went out.
The print worked out fine though but I was obviously puzzled as the Ethernet port issue didn’t happen right away.
After some digging here, I found a conversation from 2017 that brought up some great points about grounding and how static electricity can really cause havoc.
I’m removing my unshielded motor cables and using some 18/4 awg shielded cable in its place. I have just taken a break and noticed your message!
You may want to check if your printer is using unshielded and/or ungrounded stepper motors.
Apparently the static knocks the port right out.
I don’t feel like taking the printer apart so I’m down on a yoga mat soldering. Ha!
Such a great forum!