Facebook Email field return null (even if the “email” permission is set and accepted)

Question

For some users in our application, the email field returns NULL even if the user has granted the email access to the app. When we check the scope parameter and the validity

Answer 1

According to the documentation:

Note, even if you request the email permission it is not guaranteed you will get an email address. For example, if someone signed up for Facebook with a phone number instead of an email address, the email field may be empty.

That would explain why some users have a null email!