Well I guess i have found the root cause for this message after adding the admob to one of the new projects. Fortunately this is not an error, but just a warning.
And it shows up if the app google+ is not at all installed in your phone where the app runs. I guess that the admob tries to find specific ads for a person depending on its google plus account if the person has installed the app in his phone.
Or else it just throws the below message:
Failed to find provider info for com.google.plus.platform
and it continues to keep showing up the general ads.
I simply installed the google+ app in my phone and after that logged in with my account. And after that when I ran my app it is not throwing this message anymore.
And it resolved my issue.