Google OAuth is making call to Youtube API

I am trying to use Google OAuth2.0 for authentication. Everything is working fine but on initial(first) loading it is taking extra time (30 seconds-RequestTimeOut) on client side(Web-App) to load prompt. I've checked the Network Tab (Developer Console-Chrome), where I've found that it is trying to make call to

https://accounts.youtube.com/accounts/CheckConnection?pmpo=VALUE&v=VALUE&timestamp=VALUE.

This request is failing with ERR_TIMED_OUT, and In my organization we don't have access to Youtube (That I'm aware of it). But Why and Where my application is making request to Youtube API is my question. If so How do I stop this (fetch accounts from youtube)?

The scope of My App goes like this

"scope": "https://www.googleapis.com/auth/drivehttps://www.googleapis.com/auth/userinfo.emailhttps://www.googleapis.com/auth/userinfo.profile"

It is happening on initial load itself, later it is giving 200 status for the same request. What am I missing.

I'm completely new to this. (Sorry, If it is noob question)

Thanks in advance.

Edit::

I came to know why it is making request to youtube api, It is trying to fetch any other accounts(login users) from youtube(gmail-accounts). But how to stop making request to youtube(accounts.youtube.com). It is fine for my application to fetch accounts from google(accounts.google.com).

Thanks.