When return back to our website from gmail then website shows as a blank page

Hello,

I use a plugin “AJAX Login and Registration modal popup PRO” for login and they set your “AccessPress Social Login Lite” plugins for login with social like this image “https://ibb.co/0FQ512H”.

I try to login by Gmail. So when I click the button of “Login with Google” I can go the Gmail login page and also can log in Gmail.

But the problem is when it completes login from Gmail and return back to our website then the website not open and it shows a blank page. Please see the image of “https://ibb.co/Lx55drv”.
My login page here “https://els.dfp.edu.sa”.
You can see client ID and secret from this link “https://ibb.co/rZbDgZS” that I create for “Login with Google”.

Also if I already log in by any Gmail account and click the button of “Login with Google” from a different tab of the same browser then it can not autodetect the login and show a blank page like this image “https://ibb.co/5K0Ny7g”.

The page I need help with: [log in to see the link]