No FCM diagnostics when dialing *#*#426#*#*

Question

I'm currently debugging issues where FCM push messages are sporadically not delivered to my Android app. The principal setup and configuration works, most (high prio) push messages are delivered in a timely manner - but sometimes they are not.

When perusing the official troubleshoot guide (https://firebase.google.com/support/troubleshooter/fcm/delivery/diagnose/android), it advises me to dial *#*#426#*#* to get some diagnostics.

I've tried this now on three phones (Samsung Galaxy S7, Samsung XCover 4S, Motorola Moto X) but nothing happens - the phone just tries to do the call.

I've assumed that "dial this code" means "Open up the dialer app, enter this code, pick up". Was that incorrect?

Answer 1

Ok, found it.

This only works with Android's default dialer app or the Phone by Google app that can be loaded from the Play Store. The custom dialers included by some handset makers (glaring at you Samsung) can't do it.

So, to get the diagnostics: Make sure to use the right dialer.