AirPort Extreme shows nothing in app but still connected to internet
Why does apple extreme lose all info on app (does not register ) but still connects iPad to internet
This often happens in situation where the Airport is configured in bridge mode to work purely as Access Point (AP for short).
It is a common problem across any number of brand Access Points.
Tell us more info. How is the Airport configured?
It is also an issue on some later Apple iOS as they keep messing around with things.
Did you try the good old power cycle... turn it off and on again?
It is amazing how many things suddenly work when you do that.
No luck with power cycle on just the Airport then power off the modem and all the other network devices you have.. start up in correct order.. modem.. airport.. switches etc.. with 2min gap between each one.
Still no luck and you cannot get it via ethernet on a computer either.. reset it using reset button as that will always allow you to get in.. easy peasy to reconfigure if only used as AP.