The Airport Utility shows all 3 of my Wifi access points as being offline today, all have the yellow caution triangle "/!\" and display the message "Device Not Found: AirPort ExtAC was previously part of this network..."
I can prove it's wrong, I'm posting this via Wifi! And the Mac toolbar Wifi status shows I'm on my named local wireless network, and I only have these 3 access points.
Also, whenever I bring it up, it shows the Internet globe as yellow for a while, then eventually green.
If I exit and restart Airport Utility it says the same thing.
In the past, when it's misbehaved, if I REBOOT the MacBook then it works.
- I'm on a 2012 Retina Macbook the latest OS X with all application updates applied
- Wifi routers are 2 Airport Extreme AC's and one older Airport Extreme