The asus.com domain is possibly on the HSTS preload list and this affects the router as well although this device is quite different from the Asus internet pages.

Some recent threads about this issue:

• https://support.mozilla.org/en-US/search/?product=firefox&w=2&q=router.asus.com

You can try to use its IP address.

• http://192.168.1.1/

It looks like the devs added a quick fix to Firefox 105, to be released this Tuesday, so you can give it a try tomorrow to see if updating to 105 works for you.

• 1788684 - Access to router.asus.com broken as of version 104

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)

Thanks for your input. The update to 105.0 did fix the problem. I will say that I'm not exactly pleased that Mozilla locked me out of my own router from my own desktop and caused me hours of frustration.

Thanks again for your help, Bruce

Note that this was not a problem caused by Firefox, but was caused by Asus that recently had requested to get added to the HSTS preload list that is maintained by Google and that is used to determine what web servers should only be accessed via secure HTTPS.

Thanks for clarifying the cause of this issue! When I contacted Asus about this issue, I sent them the same Info that I posted here. The response I got seemed clueless, didn't address the correct issue, provided instructions on logging in instead of connecting!

Hope they've been advised of their folly!