Cable unplugged - no ethernet connection

Fusas Said:

"Cable unplugged - no ethernet connection: I have tried all, still not working"

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Thank you for the update.

A Corrupt macOS:

If the macOS may have become manipulated, technically. So, to fix that...

Reinstall the macOS:

Nothing would be deleted. It's just that items that have become corrupted or deleted, would be replaced or reinstalled, respectively. Go Here: How to reinstall macOS from macOS Recovery - Apple Support

Important:

Create a Time Machine Backup, First:

Prior to the re-installation of your macOS, be certain to backup your Mac using a Time Machine Backup. That way, you can have something to restore your Mac from, should anything go wrong with the reinstall. Use an external hard drive that is at least 1.5 the total storage capacity.

Fusas Said:

"Cable unplugged - no ethernet connection: Everything was good until the day that I changed my BT router for the new BT Fiber 100.: [...] Since that moment no more ethernet connection. I have tried new cables, old cables, and read a lot about on forums and cannot fix the problem. Can it be hardware?"

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Reset the SMC and your NVRAM:

Sometimes when changes are made to the system(i.e. updates), system configurations (i.e. for Ports) become manipulated, technically. So, reset the SMC and NVRAM.

Try Another Router:

Use different brand, and see if ethernet works (i.e. use a friend's router, with their permission). Its it works, then I would assume it is compatibility.

stevens57 Said:

"Hello, I have the same problem. I did everything that you suggest and nothin fix the problem."

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Try a different brand or router. Seems simple enough - if this all happened with a new brand router, then I would assume that would fix this.

Hello, I have the same problem. I did everything that you suggest and nothin fix the problem.