This problem is because of map api key.
You need to sign your app and find .keystore for signed app. Right click on project Android Tools->Export Signed application pachage->next -> create new keystore then use this new keysore to find new SHA1 Now find new API key for your app. And replace the old map API key with this in manifest.
https://developers.google.com/console/help/new/#installedapplications
Next time whenever you want new signed app just use this keystore no need to create new again.