Hopefully y'all can help me out. I just got ATT fiber and I want to hook my Asus RT-AC88U router to it but it doesn't want to work. If I connect to the att wifi I have Internet but if I connect to my Asus router all I get is "server not found" and there is a red light on my Asus router where it should be white when the Internet is connected.

Normally with other ISP's in the past I just hook it up and go even if the ISP modem is also a router it just plug and play and works. So I can't figure out why it's not working. Does att do some bull crap so you can't use your own 3rd party router instead of their trash?