Problem with a Cisco C9120AXI-A AP that drops the entire Wi-Fi network

[Electronic20]

Hi Community,

I have a case, in an office there are 3 AP C9120AXI-A, 2 APs are working correctly and have IP 10.77.7.22 and 10.77.7.23, but when the third AP with IP 10.77.7.25 is connected, the entire Wi-Fi network drops and the Another 2 APs no longer have service and the WLC C9800 is observed to be down.

The switch port of that AP 10.77.7.25 has to be turned off for the other 2 APs to work.

It is observed that when AP 10.77.7.25 wakes up, the WLC does not appear and on the switch port where the AP is connected, 2 IPs are observed:
10.77.7.25 with the AP's mac and 10.77.7.26 with mac 0000.5e00.0101 and if we put the IP 10.77.7.26 on THE WEB, the url appears: mywifi.cisco.com.

What could be causing this problem and how to solve it?

Your kind support.

regards

Electronica20

[Torbjørn]

I suspect that your .25 AP has an Embedded WLC(EWC) image, causing it to "hijack" your other APs from your 9800 WLC.

You need to flash a regular "lightweight access point" firmware to that AP to have it join your 9800 instead of taking the role as WLC. You can find the required downloads here: https://software.cisco.com/download/home/286322988/type/286288051/release/15.3.3-JPS 

[Electronic20]

Hi @Torbjørn 

I have the AP with this image

Would that image be okay?

[Electronic20]

HI @Torbjørn 

To complement, the AP with IP 10.77.7.23 has the same image and connects to the WLC and provides normal service, as long as I

turn off the AP with IP 10.77.7.25.

I would understand that the image is correct for the ap 10.77.7.25 shown in the first graph.

Waiting for your kind support