Why is Windows marking all assigned IPs as duplicate?

This is my home network which I configured myself; including the wiring, WiFi access points, etc. No one else has any admin access to it. It has been running for many years. I have the usual collection of phones, tablets, etc., all of which are running fine. In the past week, my Windows 11 laptop has been having issues connecting to the Wifi. BTW, it connects just fine to my office network. It is not running in domain mode. The issue it has, is that any IP I use is marked as duplicate. I have normally been using IP's assigned by ISP's router. Now, on just this PC, ipconfig shows it as duplicat

Question by Hussain Akbar on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.