Macbook M1 Ethernet is not working.

Are lights on the adapter blinking but you get no internet connection? Is that what you mean?

Are other devices connected to your LAN working properly? Are you using a new undamaged cable? What adapter are you using? The greater the detail, the greater the likelihood of an accurate response.

Your LAN (Local Are Network) carries your WiFi signal, they work hand in glove. What exactly do you mean by "Lan is also connected to the WiFi ...", that's implicit in proper setup. Please give details on your cable with lights and your adapter: maker, approximate age, history of usage. I think you're using non standard terms to describe your setup.

You get a signal from your ISP, that signal is then MOdulated/DEModulated by a modem and then distributed by a router if you have one. If your Ethernet cable connection is not compatible with your Mac port, you have to have an adapter to connect. Say an Ethernet to USB-C adapter. It's unclear where your problem is to me maybe clearer to others.

I have same problem with DELl U2722DE after that restart MACOS ethernet not working.