Connectivity to the FCM service: If your Android device loses connectivity to the Firebase Cloud Messaging (FCM) instance it will not receive Push messages sent by the 3CX Server for incoming calls and chats. This can occur due to your specific device / network environment parameters and/or connection availability to the FCM service. Please review the Google FCM requirements on maintaining connectivity to the FCM service.
The built-in device battery management: The battery / power management mechanism is specific to each device firmware and can throttle notifications or even close the 3CX app. In these cases the 3CX app cannot receive Push notifications consistently to display and handle incoming calls and chats. If you experience this issue, check the documentation for your device and update its configuration to enable the 3CX app to receive Push notifications.
To troubleshoot Google FCM delivery issues you can use the Android 'FCM Diagnostics' tool (depends on availability/compatibility):
Open the GSM phone app and go to the keypad.
Dial *#*#426#*#* or *#*#8255#*#* to open the FCM Diagnostics app.
Verify that the connection to FCM is established, i.e. the text 'Server: Connected' is displayed.
Tap on 'EVENTS' and check the log for any connectivity errors, e.g. 'Close err:6 ...'. Capture screenshot(s) to record any errors you notice and provide to your PBX administrator for troubleshooting.
- You PBX Administrator can then consult the
Google FCM requirements
and help you fix the connectivity between your Mobile Device and the Google FCM service.