Why doesn't facebook login always return email?

Question

Facebook

I am using yii\authclient\OAuth2.
When logging in, some users email is not transmitted. With what it can be connected?
public function onAuthSuccess($client)
{
$attributes = $client->getUserAttributes();
here sometimes there is no email

out the screen
should return
name
email
id
and for some users only. as the screenshot shows
name
id