In order to be "discoverable" by the AIrPort Utility, you must have both mDNS/Bonjour and IPv6 enabled on your local network.
When having difficulties accessing the AirPort thru the AirPort Utility, try the following, in order, checking for accessibility with the utility after each step:
- Check the local connection. If you are trying to access the AirPort wirelessly, make sure that you are connected to its wireless network before running the AirPort Utility to administer it. If you are still unable to access it with the utility, temporarily connect your computer directly using an Ethernet cable to one of the base station's LAN ports.
- Try accessing the base station by using the Utility's File > Configure Other… option. Then enter the LAN-side base station IP address (the default is: 10.0.1.1) and base station's administrator's password.
- Verify that both the base station and your Mac are configured for, as a minimum, IPv6 Link-local only.
- For a Mac (running macOS Ventura:) System Settings > Network > Wi-Fi or Ethernet > Details... > TCP/IP > Configure IPv6: Link-local only
- For the AirPort base station: Note: You may need to temporarily connect your Mac or PC directly to the base station by Ethernet to access it.
- From a Mac: AirPort Utility > Select the base station > Edit > Internet tab > Internet Options… > Configure IPv6: Link-local only
- From an iOS/iPadPS device: AirPort Utility > Tap on the base station > Tap on Edit > Tap on Advanced > Tap on IPv6 > Change Configure IPv6 to: Link-local only > Tap on Done
- Power cycle the base station. Remove the power adapter's plug from the power outlet, and then, wait 15 seconds before plugging it back in.
- Perform a "factory default" reset on the base station.
- Finally, if you are attempting to access the AirPort via an Ethernet connection, be sure that your Ethernet port is NOT configured for Jumbo Frames, i.e., using an MTU of 9000+.
