240AC Access Point blinking red after config

[idot]

This 240AC access point fails with a blinking red led after I configure it.

I factory reset & it brings up the config UI from the wireless side, but after config it reboots to a blinking red led again.

The only time I see my custom ssid is in the five minutes it runs before automatic reboot, and I can connect to it. But after the automatic reboot its back to nothing but a blinking red led again.

This part of our Cisco network is isolated from the Internet, if that might be an issue. I have lots of other Cisco WAPs running fine here, so I'm doubting this phone-home-or-nothing theory. And I can't imagine losing wireless intranet access on Internet-accessible sub-nets just because the ISP's Internet decides to go down. So, I'm doing something incorrectly.

Thanks for any help!

[balaji.bandi]

check the LED status :

https://www.cisco.com/c/en/us/support/docs/smb/wireless/CB-Wireless-Mesh/kmgmt-2934-cbw-startup-led-status-codes.pdf

[idot]

Thank you for the document. Yes, the 240AC is stuck blinking red. The Cisco PoE switch the 240AC is attached to assigns two sequential dynamic DHCP IPV4 addresses to the 240AC, and one of them has a MAC matching that written on the 240AC's back label.
This is a bench Cisco PoE switch with no other connections. The 240AC is drawing 4900 mW. Manufacture date: 12/2022.

Static or dynamic config on the Cisco switch DHCP server and Cisco 240AC yields the same blinking red led, despite assigning IP addresses.

It's interesting that of all the LED stages that the endless red led blink issue was noted in the document.

[idot · Accepted solution]

I have determined that this Cisco WAP 240AC requires an Internet connection to function, and that is the entire problem here. This WAP 240AC cannot function on an isolated network. The table 'Startup LED Status Codes' in the manual referenced above is incomplete: it fails to describe the duration of each phase and it proposes a lack of address assignment as the sole cause of a stuck blinking red led. My assignments are proper, and yet the infinite blinking red led problem persists. It only goes away when the Cisco 240AC has an Internet connection. Its now an RMA