@Anka82 Omada Switches do not broadcast Wi-Fi signals. Where are you seeing this error? If through the web browser, it's likely the website you are visiting does not have a proper security certificate. If in your Wi-Fi setting on your devices, are you referring to an "unsecured network" warning? 

A screenshot of the error would be very helpful in narrowing down the issue. 

Hi  @Anka82 

Thanks for posting here.

Did you enable 6G only on your AP? Please enable both 2.4G and 5G; you will then see the corresponding options. Or you can share a screenshot of the whole SSID config page

Please refer to the following to change the security mode for your wireless device.

The Weak Security and Privacy Warning on the iOS14 or iOS15

BTW, what's the model number and firmware version of your AP?