Issue with PayPal Commerce Plugin

Using Sandbox:


added Client ID and Secret  and save :

The specified credentials are valid

But on top of that I also see:

Webhook was not created, so some functions may not work correctly (see details in the log. Please ensure that your store is under SSL, PayPal service doesn't send requests to unsecured sites.)

I don't see any place to add webhook URL on this page. Also the error on log is below:

Payments.PayPalCommerce error:
{"name":"VALIDATION_ERROR","message":"Invalid data provided","debug_id":"b67e10003eac3","information_link":"https://developer.paypal.com/docs/api/webhooks/#errors","details":[{"field":"url","location":"body","issue":"Not a valid webhook URL"}],"links":[]}

So I have to add it on paypal page if so what will be the URL ?

The url is created automatically after connection. So probably there is something wrong with the credentials  used

But it says specified credentials are valid aswell.

The main error when creating a webhook is when the store URL has "http" scheme, as indicated in the notification text. In all other cases, you should contact PayPal support so that they explain what exactly is wrong with the URL since the message "Not a valid webhook URL" comes from their service.

I had exactly the same problem - resolved simply by going into Configuration > Stores, and changing the store URL from http:// to https:// (even though it was already SSL enabled).