[SOLVED] Probot on Vercel Edge: {"error":"Error: [@octokit/webhooks] signature does not match event payload and secret"}

Probot on Vercel Edge: {"error":"Error: [@octokit/webhooks] signature does not match event payload and secret"}

I have 2 Github Apps. One for dev and one for prod. The dev one works fine using smee.io. The prod one doesn't. I think my problem has to do with vercel edge, because I hosted Probot dockerized before and that worked and still works fine.

I used the example template that you can find in Probot's Github organization. The only thing I changed was js to ts and esm instead of cjs.

What I tried:

generating new secrets and private keys and setting them on vercel
creating a new github app and trying it again from scratch

I really don't know what is causing this.
See https://github.com/probot/example-vercel/issues/82 for more context.

Solution

I am not actually sure what fixed it to be honest.

I set NODEJS_HELPERS=0 and redeployed which did nothing.
I replaced the webhook URL in the github app with the smee.io URL to test it locally again which did work as expected, but when I now redeployed with the production url set in the github app it magically worked.

Really really strange.