Thanks Kevin, the app still like the same, after i set 8.8.8.8 for the DNS server. After 5-6 days connection fail, I can connect again but only for 2 days, then fail again..

@Kevin_Z Hi Kevin, thanks for your reply, the error message "Unable to connect to the device, please try again" and sure the internet connection is very good. And in the app, I can see the device is...

I can successfully install the app and add my device into the "my device" list, the app show it is a cloud device . The problems is when in home "wifi" connection, the app can login to the device...