Facebook page leadgen webhook returns error 102 Server Failure

One recent change (as of May 1, 2018) is that the app Status must be "Live" in order to receive actual webhook updates. If it is left "In Development", webhook requests will now fail with error code 102 "Server failure" (such a helpful message!), and the Webhooks page for the app (https://developers.facebook.com/apps/{your app ID}/webhooks/) will show a message saying:

Applications will only be able to receive test webhooks sent from the app dashboard while they are in development. No production data, including that of app admins, developers, and testers, will be delivered unless the app is live.

It took me a while to figure that out since the webhooks had been working previously. Hope this helps some people!

I know this is really old but I came across the same issue and this is what I found.

"You can use this tool to create and delete test leads for your forms; however, you cannot use the tool in developer mode."

Basically saying you will get that 102 message if you're in dev mode, which makes no sense why they would have a testing tool you can only use when your app is "live".

Ok I found the problem.

Although my app was correctly subscribed to the page with all valid and never expiring tokens, one authorization was missing.

If you encounter the same problem follow those steps :

-> go to business manager
-> go to busienss settings
-> go to leads access tab
-> select your page
-> click "CRMs"
-> Select your app and assign access

Hurray

While subscribing my page to Facebook app I've set leadgen_fat instead of leadgen and got this error.

Add retrieve_leads to your scope on login and be sure that your app has this permission.Then add leadgen to subscribed fields.

https://stackoverflow.com/a/54713182/7313872

I solved the issue, this was the problem here the RTU debug tool was not working until I made my app to LIVE status then it was working properly . Also on the FB docs its clearly showing

When you previously used the Facebook documentation for the webhooks startup, the platform.php file code would subscribe you to "feed" and not "leadgen" so check that you have the correct subscription code. I logged the bug in their documentation and looks like they have fixed it.

https://developers.facebook.com/support/bugs/681262475926363/

https://developers.facebook.com/docs/marketing-api/guides/lead-ads/quickstart/webhooks-integration/

FB.api(
  '/' + page_id + '/subscribed_apps',
  'post',
  {access_token: page_access_token, subscribed_fields: 'leadgen'},
  function(response) {
    console.log('Successfully subscribed page', response);
  }
);

Also check that

1. Your app is live and through review
2. You have all the permissions.
3. You are subscribed to the correct type aka "leadgen"
4. Your CRM has been given access to leads and manage pages by the Business Manager Account, owner or client.

I resolve the problem whit next CURL.

Register app to page:

curl -i -X POST "https://graph.facebook.com/{pague_id}/subscribed_apps?subscribed_fields=leadgen&access_token={token_id}"

leadgen field is very important

The response on my server is good!

{"id":"XXXXXXX","time":1606958566,"data":{"value":{"form_id":"7415707530XXXX","leadgen_id":"891990681XXXXX","created_time":1606958565,"page_id":"375141142501174"},"field":"leadgen"}