Failed to Resolve Com.Android.Support:Appcompat-V7:22 and Com.Android.Support:Recyclerview-V7:21.1.2

failed to resolve com.android.support:appcompat-v7:22 and com.android.support:recyclerview-v7:21.1.2

These are the correct version that you can add in your build.gradle according to the API needs.

API 24:

implementation 'com.android.support:appcompat-v7:24.2.1'
implementation 'com.android.support:recyclerview-v7:24.2.1'

API 25:

implementation 'com.android.support:appcompat-v7:25.4.0'
implementation 'com.android.support:recyclerview-v7:25.4.0'

API 26:

implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support:recyclerview-v7:26.1.0'

API 27:

implementation 'com.android.support:appcompat-v7:27.1.1'
implementation 'com.android.support:recyclerview-v7:27.1.1'

Failed to resolve: com.android.support:appcompat-v7

Well, I resolved the problem by changing the version of the appcompat-v7 and design repositories to 22.0.1 from 22.2.1. 22.0.1 is not a valid dependency version.

In my gradle file ->

compile 'com.android.support:appcompat-v7:22.0.1'
compile 'com.android.support:design:22.0.1'

Changed this to

compile 'com.android.support:appcompat-v7:22.2.1'
compile 'com.android.support:design:22.2.1'

Failed to resolve: recyclerview-v7

Finally I found a solution. Upgrading all the support dependencies to the latest version, solved the issue. You can check the latest version of dependencies here. I upgraded the support dependencies to the latest version 28.0.0-alpha3. It solved my problem.

failed to find: com.android.support:appcompat-v7:22.2.0

Just update your support library and support repository & your SDK Manager ,
Then

compile 'com.android.support:appcompat-v7:22.2.0'

Please check this SO Answer

Android Studio Failed to resolve: com.android.support:support-core-utils:23.2.1

You're getting this error because the support-core-utils library was part of the v4 Support Library in v23.2.1.

With the release of v24.2.0, the v4 Support Library has been split into several smaller modules one of which is support-core-utils. For more information on the split check the following link: https://developer.android.com/topic/libraries/support-library/revisions.html#24-2-0-v4-refactor

So the solution to your issue is to use a newer version of support-core-utils library such as 25.0.1.

Failed to resolve only recyclerview

You have a typo in your dependency, a dot instead of the colon after the group ID.

It should say:

compile 'com.android.support:recyclerview-v7:21.0.0'
                            ^

Also, consider using the latest versions (22.2.0) instead of 21.0.0.