Facebook Webhook test send not working?

Question

I am creating a Facebook Webhook. The callback link has been verified and so the connection should be okay.

When I further test the Webhook by pressing the test button under feed,

it seems it works.

However, nothing's received in my server, not even an access log in Apache. (I have checked both ssl_access_log and access_log) Any suggestion on what I have possibly missed?

Answer 1

It turns out to be the problem of using vhosts. The vhosts is set up by my colleague and he decided to save the access log and error log putting in other position than the default location.