Facebook login not working for new users

Hi.

My website for https://universityrevisionguru.co.uk/ facebook login has stopped working for new users.

I have the correct FB APP Id, app secret and oauth redirect urls all set up.

When trying to login here: https://universityrevisionguru.co.uk/my-account/
with a existing user, there doesn’t seem to be any problem.

However, when trying to login with a new user (i.e. a Facebook account that has never been used with the website before), the pop up will appear and will just stay loading.

Note this does not seem to be an issue for any existing customer already linked with Facebook.

Versions

• WordPress: v4.9.5
• Super Socializer: v7.11.10

This has cost us a lot of customers recently, so it’s a very urgent issue.
Thank you for your help.

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