I’m unable to pass the URL verification required by the Events API, as described here.
I tried the json and text response (also by forcefully setting the Content-Type to text/plain for text, as this was different in N8N’s text response for the Respond to Webhook node).
I curl’ed the request myself to see if the request was responding correct, and it was - the only different being that n8n returns 200 and not 200 OK. Especially because Slack says the request URL responded with a HTTP error, it seems it’s parsing the response code.
Thanks for your response. I honestly do not see the difference between yours and mine?
It seems to be exactly the same, the only difference being that I use the item’s value in Respond to Webhook instead of referencing to the first node. And, the webhook URL is different.
I fully recreated yours now, but there is no behavioural difference:
and the Respond URL verification still shows the correct challenge:
Besides the above, I think I now know partially what is going on, but not sure why: it seems Slack is retrying the URL verification hook. That is why with the webhook-test it fails with a HTTP error (because the second try it fails as the workflow not being executed). With webhook it seems to retry 3 times and then fail with the error below.
I observed this behaviour as well in my testing, but forgot to mention.
We have 2 Execution Process options, Main and Own. The default is own which can be a bit slower depending on hardware / resources which will create a new thread for the workflow so if Slack is calling it might take up to 3 seconds for the workflow to fire up. If you set EXECUTIONS_PROCESS to main though it will run all the workflows in the same process and will be a lot quicker.