can't reset admin PW for AX4200 router

I try to login to my Orbi RBR750 on a browser set to 192.168.1.1. It asks for a name and PW, I enter "admin" and a password(that doesn't work). After a few attempts it has me put in the serial number to reset the password. I answer a couple security questions and then edit a page to create a new password. I put in a new password (twice) on the this page but when I then I then try to login using "admin" and the new PW it still fails. I've tried a couple different browsers and many times, but no luck. 

The help says if I click on "cancel" at the login page and enter the serial number, it will show me the current password. But that doesn't seem to happen