Cannot Connect to Router via Browser

I have never before logged onto my router. After trying to for the very first time I found that I cannot log onto my router via either my iphone or imac. Everytime I do I get the message:

"401 Unauthorized - Access to this resource is denied. Your client has not supplied the correct authentication."

And then it asks me security questions that I never created answers for. I tried doing multiple factory resets of the router but that does not change anything. Neither the supposed default password "password" nor the default wifi password on the device sticker works with the default username "admin." I have tried multiple browsers. I have tried clearing my history, cache, and cookies.

Any ideas what might be wrong or what I could do? Any help would be greatly appreciated.