In this case, it is always necessary to proceed exactly according to the user manual.
1) First of all, you need to check that the camera Wi-Fi is turned on.
2) Do not activate the Wi-Fi application on your mobile phone, but instead find the camera in your phone's Wi-Fi settings and connect to it (the default password and Wi-Fi camera name can be found in the user manual).
3) Once a successful connection to the Wi-Fi camera has been established then you can you launch the application on your mobile phone.