Wifi 5 GHz channel 0

(english is not my native language)
I have an EX6200v1 and I use it as access point.
I can't set or change the channel. Now the channel is set to "0" as you can see.

Connection to Existing Network (5GHz)

    Connection Type Ethernet
    Connection Status Connected


Access Point Wireless Settings (5GHz)

    Name (SSID): Extender5
    Region: Europe
    Channel: 0
    Wireless mode: Up to 867 Mbps
    Wireless AP: On
    Broadcast Name: On
    Wi-Fi Protected Setup: Configured

The extender's firmware version is V1.0.3.76_1.1.111

Whenever I try to change or set a channel I receive this message "You select a DFS channel, the channel will be changed automatically if any Radar is detected.".
I've tried all the channels and nothing worked.

I have an ex6150 and I don't have issue with its 5GHz.

Please help me.