My Archer C1200 v3.0 router stopped working with IPv6 yesterday. I cannot get it to obtain a public IPv6 address. If I connect my computer directly to the modem without the router, I get perfect IPv6 connectivity, so the issue seems to be router related. IPv4 is working normally with and without the router.

Here is a screenshot of the router's IPv6 settings. Clicking Release and Renew doesn't seem to do anything.

https://imgur.com/a/r4ad8PH

Some additional info:

1. The only things that I changed in the last few days were

a) I moved some devices around and in the process I disconnected and reconnected my cables and devices.

b) I attached a new USB drive to the router as a shared device

2. My ISP is Comcast. My computer is running Windows 10. All drivers and firmwares are up to date.

3. I tried the various solutions I found online (release and renew IP Config, reset TCP/IP, reset Winsock and IPv6); they have not worked.

4. When this problem initially arose, the Windows ethernet status indicated "No internet access" for IPv6. As I was trying various solutions I read online, I ran "ipconfig /release6" and "ipconfig /renew6," and got an error when trying to renew6. After I restarted my computer, modem and router, the ethernet status now reads "No network access" for IPv6.

Any help would be greatly appreciated!