Hello @Newbie Dev
I believe it is because the https://locahost:port number/
is not a publicly exposed URL. In order for Webhooks flow to work the way you want, you'll need to expose a public IP from your local network, and use it to construct a Webhook URL to receive notification-related requests from Azure.
However, instead of Webhooks, a much better approach looks to me is to use Azure Event Hubs for facilitating the notifications, check out the following doc: Get change notifications delivered in different ways
And as for converting your HTTP Triggered function to Even Hub triggered one: Azure Event Hubs trigger for Azure Functions
I hope this is helpful, let me know if any further queries!