We're using Event Notification Service to declare a webhook, which will handle every link click in ou email. We are using the REST API (Node.js) to do so and it works.

After a successful registration we receive the following body :

callbackName: '---',
callbackId: '---',
url: '---',
signatureKey: '---',
maxBatchSize: 1000

We then use the callbackId and signatureKey as parameters for verifying the webhook, mandatory step before subscribing to events.

But our verification code always receives the following :

message: 'MCMS_UWH_Runtime_ObjectNotFound_callbackNotVerified: Callback not verified', errorcode: 30003

And when listing our registration it is actually not verified and thus non-usable for subscription.



2 Answers 2


Simply use MC front end, in setup :

enter image description here

From there, you can:

  • Register a callback
  • Verify it
  • Declare the events you callback will receive

No code required


You are surely using the Signature Key returned after registering you callback, when you should actually use the Registration Key your end point receives during the registration. Those are different.


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