If you can’t get to your router’s admin page using the Edge browser, there’s a reason why. Microsoft broke it with this month’s cumulative updates.
Yesterday, Microsoft appended this warning to all of its Windows 10 January cumulative update pages for version 1703 onward:
After installing [this month’s cumulative update], some users report that they cannot load a webpage in Microsoft Edge using a local IP address. Browsing fails or the webpage may become unresponsive.
