Resolve issue Failed to load map. Error contacting Google servers. This is probably an authentication issue.

It have problem with your API_KEY which is obtained from Google API Access ,so verify your API_KEY , certificate fingerprints and package name.

If your API_KEY and certificate fingerprints and package name is correct and still get this issue Failed to load map. Error contacting Google servers. This is probably an authentication issue. Try this

use this inside <manifest>

<uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" >
    </uses-feature>

 <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />