As of right now I removed the WiFi 6 Accesspoint in from my Omada Controller. I am using it in Standalone-Mode because then you can disable WiFi 6 otherwise this error keeps occurring. These are the settings from the AP:

AND

I will request disabling WiFi 6 through the Omada Controller.

andrei.cmn wrote

  @Tobias16 I think I figured it out.

The issue is not WIFI ax/ac handover, rather the WPA encryption. The WIFI 6 EAP will default to using WPA3, while the others will only be able to use WPA2.

Under Settings - > Wireless Networks -> WLAN go to each network that is active on the 5Ghz band and edit it.

From there disable the 6Ghz Band and make sure security is set to WPA Personal. Then under Advanced Settings select WPA/WPA2-PSK/AES instead of WPA3.

This fixed the issue for me and now I can roam between APs without any issues (tested with a Macbook Air M1, iPhone 12 and a iPhone 12 Pro).

 

Hope this helps you too.

@andrei.cmn Thank you so much for this. This issue was driving me totally insane, and this has resolved it. 

For anyone seeing "Unable to connect to wifi" and messages about radio contention on iPhone on WPA3 being disabled on Android, this is the resolution - disable 6ghz on the wireless network and lock in WPA2/AES, not the WPA2/3 hybrid.

 I tried every possible fix out there untill i fixed it by forgetting the Wi-Fi network and join it again.

Hi,

I had the exact same issues. Turning off 6Ghz and WPA3 solved the issue for me. I had to forget the network and rejoin it.

I think this is related to WPA3. Apple uses WPA3 if it is available. But if you used WPA3 for a network at least once, the OS always want to use WPA3.

Sadly no idea, how to use Wifi 6 Access Points, when there are APs which don´t support Wifi 6 using the same SSID.