Microsoft Edge is what Windows 11 includes. and discontinued browser as of Windows 11. The only thing I can think of is Adobe has hard coded the licensing to work ONLY with Internet Explorer 11.
I've also tried the registry values that Adobe suggests we add to fix the 'your browser isn't up to date' prompt. I've uninstalled Fireworks CS6 thru Creative Cloud and downloaded the offline installer and put it on that way. I've run the Adobe Cleaner app and cleaned Fireworks CS6 off. I've tried signing out and back in of the Creative Cloud app with my Adobe ID.
I've clicked Managed Activated Devices, which just takes you to the webpage. and when you select option 2 (I've already signed out), it just flashes and brings up the same 2 choices. When you select option 1 (Sign me out), you get the 'You're not updated' dialog that says you need to update your browser first. stating I've already activated it on two PCs. Yet when I run Fireworks CS6, it brings up the exact same window above. I have deactivated the old computer in the /activated-devices website and it now only lists the one new Windows 11 PC there. I just purchased a new PC that came with Windows 11. I am also now having this issue with Fireworks CS6 thinking there needs to be an update.