AirPort Extreme is disconnected from the internet when in bridge mode I have to use the router provided by my ISP to connect to the internet, but I also want to use my AirPort Extreme.

DHCP is set to on in the ISP's router. When I connect the router to the AirPort, and set the AirPort to DHCP and NAT, it seems to work fine, but it also says Double NAT.

So I found out that I needed to turn off one of the DHCP servers, and decided to put the AirPort Extreme to Bridge mode. But when I do that, I get no internet connection. In the AirPort Utility, the Internet light is yellow and it says connection disconnected. It also shows the DNS servers as 192.168.1.1 which I guess is the router's IP address.

Why does this happen? What could be causing the problem?
This is not a real solution, but it might help if you have the same issue.

I still get the problem, and every time I get it, I restart the AirPort Extreme (by unplugging it from the outlet, waiting a bit, and plugging it back), and it works (until it stops working again). This happens around once a month or every other month, so it is not a big deal for me now.