Simple question. When I attempt to create a webhook subscription (https://developer.squareup.com/console/en/apps/[app_id_here]/webhooks) I get this error:
“An error occurred while creating a new webhook subscription.”
All the required fields are filled out. 
@adns What is your application ID? Happy to take a look into this!
Thanks so much. I found that it was failing because my URL wasn’t yet published and it apparently checks for reachability before allowing creation of a new webhook. The error just doesn’t surface that fact. All good now!