lost wifi username

The logins for the router and WiFi are not the same thing. They are totally independent of each other. You have to log into the router to make any changes to the wired and wireless network.

Curious said:

But I cannot connect to the Asus router to make changes. Neither cable or wireless connection will login from my windows 10 laptop. I now the password is correct. But the username must be wrong even though I wrote it down.

I agree with the others.
You seem to be mixing up the password for connecting to the network with the webgui password [& username] to log into the Admin function of the router even though they are two entirely separate things.
In other words, Yes, the webgui login originally used to set up the mesh network is different from the wlan login.
Your router manual will almost certainly give you the default name of the Admin function of the router and will probably also tell you if you can change it. I have never had a router that allowed me to change it.

As Helmut said, you might have left a trace of your webgui password for the Admin function of the router in Windows credentials.
You might also have left it in the saved passwords list of your browser.
If such clues do not solve the problem then consider why the webgui password you wrote down might not be 'correct'. Did you have a different keyboard layout at the time [e.g. you typed " to get @ or the other way around]?
Windows does not have a reveal the webgui password for the Admin function of the router function so you might end up being forced to reset the router if you need to alter any of its webgui Admin settings.


Best of luck,
Denis