If you have previously connected your EOS, PowerShot or IXUS camera to either the EOS Remote or CameraWindow App you will experience a connection failure when attempting to connect the same camera to the new Camera Connect App.
To resolve this the previous connection settings for either EOS Remote or CameraWindow stored on the camera must be removed to enable a successful connection to Camera Connect. To remove these settings you need to access the Wi-Fi settings in the camera menu and select 'reset all' available connections. Once complete access the Wi-Fi screen in playback mode and select the smartphone icon, connection to the App can now continue as normal.
Full details on how to edit or erase Wi-Fi settings for each Canon camera are contained in the full product manual which can be downloaded from the 'Manuals' tab above.