Webhook handler failed. View function logs in Firebase

Question

Good, I wanted to know if someone can solve me this problem with Stripe and Stripe extension in firebase. Every time I complete a purchase in the session.checkout.completed event it returns the following:

{
  "error": "Webhook handler failed. View function logs in Firebase."
}

But then I go to the firebase cloud functions log information and it reports the following:

[Error]: Webhook handler for Stripe event [evt_1Kyyt1DsP1EUbu1sCFBns09Q] of type [invoice.payment_succeeded] failed: User not found!

I know it's not a lot of information but what else can I contribute since it's something firebase does.