Confirm device is powered on.
Confirm the device is reset to pairing mode and the indicator light is blinking.
Make sure that the signal of the network environment where the device is located is strong and stable. Put the device, smartphone and router closer to each other.
Confirm that your smartphone is connected to a correct Wi-Fi frequency (some device only supports 2.4GHz).
If you are using iOS 14, please make sure you have opened the local network permission and wireless data permission of the App.
The router may have other special authentication methods, such as MAC authentication, AP isolation, etc. In this case, you need to modify the advanced settings of the router or contact your ISP (Internet Service Provider) to cancel the special configuration.