No test label_callback_url from Easyship to my webhook URL

Hi, my name is Mikhail, I've already implemented functionality of requesting labels to my store, but there is no request from Easyship to the webhook URL that I specified in my Easyship dashboard. According to the this section of documentation https://developers.easyship.com/docs/label-callbacks-for-warehouse-integrations, after I create webhook in my Easyship dashboard, there is must be a test request from Easyship to this webhook URL for approve it. But I retrieve no request and can't completely finish labels functionality. Maybe I've done something wrong with specifying webhook URL.
Best regards, Mikhail Denisov