Why am I getting the 'FCM registration error: Failed to retrieve token' on Android?

This error means your app cannot obtain a push token from Firebase Cloud Messaging (FCM). It is almost always an incorrect Firebase configuration in the Android project.

1. Verify google-services.json

• Location: put the file in your app module directory — app/ in a native Android project, or android/app/ in a Flutter / React Native project.
• Content: make sure the file comes from the correct Firebase project and that package_name inside it matches your application's applicationId exactly.

2. Apply the Google Services Gradle plugin

Use the syntax that matches your build scripts. The current plugin version is 4.5.0; use the latest available rather than pinning an old one.

Kotlin DSL (build.gradle.kts) — recommended:

1. Project-level build.gradle.kts:

   plugins {
       // ... other plugins
       id("com.google.gms.google-services") version "4.5.0" apply false
   }
   

2. App-level app/build.gradle.kts:

   plugins {
       // ... other plugins
       id("com.google.gms.google-services")
   }
   

Groovy (build.gradle):

1. Project-level build.gradle:

   buildscript {
       dependencies {
           // ... other dependencies
           classpath 'com.google.gms:google-services:4.5.0'
       }
   }
   

2. App-level app/build.gradle:

   apply plugin: 'com.android.application'
   // ... other plugins
   apply plugin: 'com.google.gms.google-services'
   

3. Check the Pushwoosh side

Make sure the Android platform in your Pushwoosh project is configured with the FCM v1 service account JSON exported from the same Firebase project (legacy Server Key / Sender ID configuration was discontinued by Google in June 2024).

Then clean and rebuild the project. This resolves the token retrieval error in the majority of cases.