@ShockWave3 did you fix the problem with verifying the url from self hosted n8n? Thanks
I’m unable to get this working as well. Could it be that n8n response with HTTP/2 200 and Slack expects HTTP 200 OK?
Hey @Wouter0100,
Welcome to the community 
Would you be able to pop open a new thread and include what you have tried? This will help us focus on the issue you are seeing without having to worry about the history from this thread which may not be directly relevant to your issue.