Error : Google.JarResolver.ResolutionException: Cannot find candidate artifact for com.google.android.gms:play-services-games:9+

I trying to add the google play services to my project . Every time when I switch to android on the build settings in the project I get this error : Google.JarResolver.ResolutionException: Cannot find candidate artifact for com.google.android.gms:play-services-games:9+ at Google.JarResolver.PlayServicesSupport.DependOn (System.String group, System.String artifact, System.String version) [0x00000] in :0 at GooglePlayGames.Editor.GPGSDependencies.RegisterDependencies () [0x00000] in C:\Users\Public\Documents\Unity Projects\Google Play test\Assets\GooglePlayGames\Editor\GPGSDependencies.cs:57 at GooglePlayGames.Editor.GPGSDependencies..cctor () [0x00028] in C:\Users\Public\Documents\Unity Projects\Google Play test\Assets\GooglePlayGames\Editor\GPGSDependencies.cs:49 UnityEditor.EditorAssemblies:SetLoadedEditorAssemblies(Assembly[])

and this error

I don't know what to do from here . I need help. Assets/GooglePlayGames/Editor/GPGSUpgrader.cs(194,80): warning CS0162: Unreachable code detected

I have updated everything . Here is a pic