Android - Getting multiple errors while building the project

Question

I am getting these errors while building the project

1. Failed to resolve: firebase-core
2. Failed to resolve: multidex
3. Failed to resolve: play-service

Answer 1

Have you tried rebuilding the app? Also make sure you are using the latest version of GMS. As a sidenote you dont need to add the entire gms library, you can add selective services. I see you have added gms- and gms-ads, which would already be included in the main gms.

Answer 2

Apparently, jcenter has started mirroring Google's repo. Try moving google() before jcenter() in the allprojects section of your project's build.gradle (like this):

repositories {
    google()
    jcenter()
    maven { url "https://maven.google.com" }
    maven { url "https://jitpack.io" }
    maven { url  "https://adcolony.bintray.com/AdColony" }
    maven { url "https://dl.bintray.com/ironsource-mobile/android-sdk" }
}