Failed to Resolve: Com.Google.Firebase:Firebase-Core:16.0.1

Failed to resolve: com.google.firebase:firebase-firestore:16.0.1

To solve this, please change the following lines of code:

implementation 'com.google.firebase:firebase-core:16.0.1'
//dependency for using firebase database
implementation 'com.google.firebase:firebase-database:16.0.1'
//dependency for email and password authentication
implementation 'com.google.firebase:firebase-auth:16.0.1'
//dependency for cloud storage
implementation 'com.google.firebase:firebase-storage:16.0.1'
implementation 'com.google.firebase:firebase-auth:16.0.1'
implementation 'com.google.firebase:firebase-firestore:16.0.1'

implementation 'com.google.firebase:firebase-core:16.0.6'
//dependency for using firebase database
implementation 'com.google.firebase:firebase-database:16.0.6'
//dependency for email and password authentication
implementation 'com.google.firebase:firebase-auth:16.1.0'
//dependency for cloud storage
implementation 'com.google.firebase:firebase-storage:16.0.5'
//implementation 'com.google.firebase:firebase-auth:16.0.1' //Removed
implementation 'com.google.firebase:firebase-firestore:18.0.0

Please don't also forget to add the as the last line in your file:

apply plugin: 'com.google.gms.google-services'

Failed to resolve: com.google.firebase:firebase-messaging:16.0.5

firebase-messaging 16.0.x version seems unavailable, That why we
getting the error
"Failed to resolve: com.google.firebase:firebase-messaging:16.0.5"

In order to fix it keep the other 16.0.x versions as it is

and upgrade 17.x.x versions to the latest

code is given below

def Firebase_Auth_Version = "16.0.5"
def Firebase_Messaging_Version = "17.3.4"

 implementation "com.google.firebase:firebase-messaging:$Firebase_Messaging_Version"
 implementation "com.google.firebase:firebase-auth:$Firebase_Auth_Version"

Failed to resolve: com.google.firebase:firebase-core:16.0.1

From the docs:-

Your app gradle file now has to explicitly list com.google.firebase:firebase-core as a dependency for Firebase services to work as expected.

Add:

 implementation 'com.google.firebase:firebase-core:16.0.1'

and in top level gradle file use the latest version of google play services:

classpath 'com.google.gms:google-services:4.0.2'

https://firebase.google.com/support/release-notes/android

https://bintray.com/android/android-tools/com.google.gms.google-services

Note:

You need to add the google() repo in the top level gradle file, as specified in the firebase docs and also it should be before jcenter():

 buildscript {
  repositories {
          google()
          jcenter()
      }

dependencies {
  classpath 'com.android.tools.build:gradle:3.1.3'
  classpath 'com.google.gms:google-services:4.0.2'
   }
}

allprojects {
     repositories {
              google()
             jcenter()
  }
}

task clean(type: Delete) {
  delete rootProject.buildDir
 }

https://firebase.google.com/docs/android/setup

Failed to resolve: com.google.firebase:firebase-core:16.0.5

From https://firebase.google.com/docs/android/setup it looks like 16.0.4 is latest version

com.google.firebase:firebase-core:16.0.4

Why I am getting this Could not find com.google.firebase:firebase-core:16.1.0. error all the time?

Could not find com.google.firebase:firebase-core:16.1.0"

It happens because firebase-core:16.1.0 doesn't exist (today).

You can check the latest version here. Currently it is 16.0.7

Firebase Core com.google.firebase:firebase-core:16.0.7

Change your dependency in:

implementation 'com.google.firebase:firebase-core:16.0.7'

failed to resolve: com.google.firebase:firebase-core:16.0.0

I notice you need to updates a lot of your scripts.

For example, let's start with your top-level build.gradle. You should no longer use android gradle plugin 2.+, instead you should use version 3.1.x

And to do that, you should put google() in your repositories.

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
   repositories {
      jcenter()
      //Add this line
      google()
   }
   dependencies {
      //Please update it to 3.1.x
      classpath 'com.android.tools.build:gradle:3.1.2'
      //Update to the latest version as well
      classpath 'com.google.gms:google-services:4.0.1'
      // NOTE: Do not place your application dependencies here; they belong
      // in the individual module build.gradle files
   }
}

Some tips:

Try to update your app-level build.gradle, from compile to implementation since they will be deprecated soon.

Failed to resolve com.google.firebase:firebase-database:16.0.1

Try adding google() repo in top level gradle file :

buildscript {
// ...
dependencies {
// ...
classpath 'com.google.gms:google-services:4.0.1' // google-services 
plugin
  }
}

allprojects {
   // ...
   repositories {
   // ...
   google() // Google's Maven repository
 } 
}