Incoming Webhook not working

Hi all,

I created an Incoming Webhook URL for a Glip group, but it just can't pass the test.

Tried this command in the terminal, I'm using a MacBook.

curl -d '{"text": "sdfsd"}' -H 'Content-Type: application/json' my_webhook_url

It has an error message like the below:

{"status":"error","message":"Your request was accepted, however a post was not generated","error":"Invalid Custom payload: no supported fields","validation":[]}