I had a strange problem two days ago. Ethernet stopped working, but Wi-Fi is ok

[Sarma]

I have been using my home CAT5 network for for almost 25 years. I used several routers such as TP link, Negear and Cisco. Three years back I switched to ASUS Mesh and I was happy until two days back - suddenly, the ethernet connection (all three ports) stopped working. None of the devices such as T-Mobiles booster, Sony TV, TCL TV, Roku Ultra, Amazon stick, etc. work anymore. The PC gives weird "unidentified network with no internet" that was getting IP from DHCP of the router.

What is happening suddenly? Please someone could help me. Thanks in advance.

SP

[Sarma]

Resolved with no clue - I turned off ASUS router for half day. I restarted with ethernet cables unplugged. I then added two of them (tat are near to the router). THOSE TWO worked suddenly! Then I added the last one that runs to the family room where my PC, Roku Ultra and Sony TV are connect. On the PC, I am getting "unidentified network" error & both TV and Roku are not able to connect over 'wired'. SO, I suspect something is happening that particular wiring. (that runs thru house attic).  I will check it later. For some reason, the entire ethernet segment stopped working.