In order to access your router that is currently in bridged mode you need to manually assign an IP address for your computer that’s plugged into it. This is because in bridged mode your router doesn’t automatically assign your computer an IP address.
So if your router has an IP of 192.168.1.1….
Then on a windows PC set your Adapter to 192.168.1.X (X can be replaced with a number from 2 to 254 as long as it’s not the same one as your router). Then set the subnet mask to 255.255.255.0. That’s all you have to do!
Then try logging into your router via web interface again.
If that doesn’t work try typing in http://192.168.1.1
or whatever your router ip address is in incognito mode on your browser.