Zendesk webhook trigger in n8n return error when publishing the workflow

I've created a workflow in n8n that returns an error everytime I try to publish it.

I've narrowed it down to that it is your webhook trigger that causes the error. If I remove all other nodes from my workflow, I still get an error when trying to publish the workflow.

When I execute the workflow for test the trigger works perfectly fine. I just can't publish it. 

These are the two errors:

"Problem activating workflow
The following error occurred on workflow activation: Bad request - please check your parameters"

"Workflow could not be published: 400 - """