Why is the lan cable disconnected?

Question

System administration

Good afternoon, sometimes the lan cable is disconnected, the light on the switch does not light up. When the connector is re-plugged, the connection appears (maybe for a week, maybe for a couple of days).
Once on the switch, the green light blinked once every 10 seconds, as if something was being transmitted, but quickly turned off
. Once it was necessary to re-plug it on the router (it did not help on the switch
) .
Replaced both the router and the switch, but the problem still remains. I think it's a cable, but how can I check it 100%? Or can you recommend something else?
I can’t try another cable (it’s impossible for the wire to be visible in the organization) the distance between the router and the switch is more than 15m
The router is now a microtic, there was an asus and zyxel before that
tp-link switch
Asus nettop PC with Windows 10, and the other 15 nettops do not behave this way

Answer 1

You can start by re-crimping the ends of the cable

Answer 2

There was a similar topic. They also suffered.
The problem was that a copper-clad cable was purchased for laying highways. He is very tough. And the aluminum core is oxidized with a copper connector.
And there is also a cable for hidden laying patch panel - socket. This cable is single core.
And for patches, the cable is soft with a few strands inside.