On the attachment image you can see the log error of the browser console.
Thanks for your contacting us.
We are so sorry for late response because we need much time to check your issue.
For your question: Because you have added the wrong Facebook API causing this issue. We also added our API key on your site, it works fine and the facebook login works fine.
In this case, you need to create a new Facebook API key correctly. We still remained our API key so you can check it.
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