@Vincent-TP hi Vincent,all, thank you for reply. I will continue with Wifi Analyzer, but actually started following different troubleshooting route. With my Telco I could get Plume Wifi Pods, trying...

Hi, 4 EAPs are cabled to two Omada switches, who connect to my telco router. Also an OC200 controller is added. Still I have often disconnects on iOS devices, it is very difficult to manage my SONOS...