We've just checked with different browsers, and don't find such an issue, everything works as expected. See the recorded video below:

https://www.screencast.com/t/yoaeC0E9E58

Also please note, never use incognito mode with Google + login or other login buttons. Google + login button doesn't work on incognito mode, it cannot add cookies and start the session. 

here is the URL for the connect with Google +:

https://accounts.google.com/signin/oauth/identifier?redirect_uri=storagerelay%3A%2F%2Fhttps%2Fsirajgraphy.com%3Fid%3Dauth392428&response_type=permission%20id_token&scope=email%20profile%20openid&openid.realm&client_id=1062082352201-k7im55dsfc0uamgtacc8n240nh1tf8oc.apps.googleusercontent.com&ss_domain=https%3A%2F%2Fsirajgraphy.com&fetch_basic_profile=true&gsiwebsdk=2&o2v=1&as=aziiEx5JMPH0yfZImUIvDg&flowName=GeneralOAuthFlow

And I made sure it's enabled:

Please leave the example URL, and make sure the  Google + social login is enabled, to allow us to check it.

I have followed the instructions here to enable Google + account login for wpDiscuz

and after that what I try to login it shows me this error:

Then I added my website URL in the "Authorized JavaScript origins" and it worked I can see the login option to google, but after I login nothing happen and it my website it shows loading icon beside connect with Google +

Kindly see this my settings is it correct?

Also I have added the “Authorised redirect URIs” as below:

https://sirajgraphy.com/wp-admin/admin-ajax.php?action=wpd_login_callback&provider=google

Thanks.