Be sure it reset. Press and hold the WPS/reset button for at least 7-10 seconds (longer is better). The the router should reboot and when you get the sign on page, enter admin as the userid and admin for the password. Then you will need to set up your settings again.

I did do this. But now I know longer get asked for a username and it only real ask me

for a password. The default password does not work.

 

Something is not right the login screen looks different from before. I did upgrade the firmware a while back but this is the first time I am resetting it again since an upgraded

Depending on version level, the user interface changed a while back from blue to green and the options are different. The few times I needed to reset a router, the above worked. Did your router allow for password recovery? see https://static.tp-link.com/2018/201801/20180125/1910011900_Archer%20C8_UG_V3.pdf Not sure if this may help or not but it is what I would try. Disconnect all of the cables to the router except the one to your PC. Power down the router and up and see if you can sign on. Then I would think a call to TP-Link Support may be needed.