invalid url for webhook

i am trying to create a webhook in Zapier for my Acrobat sign account. 
I created the application and gave al the permissions, but when i create the webhook and input the zapier url i get an error from adobe that says 
The URL provided is not a valid Webhook URL.
But i have used this setup before and not had this issue, i have been working on this for hours trying to find an answer and i desperately need some help.