[SalesForce] Publicly exposed Rest class does not support post method

I want to expose a Rest service class with a method with @HttpPost annotation.
Below is the code snippet for what I am doing

@RestResource(urlMapping='/webhook')
global class Services {
    @HttpPost
    global static String createNewCase() {

     return 'Done';
    }
}

But When I call these services, this throw error

[
  {
    "errorCode": "METHOD_NOT_ALLOWED",
    "message": "HTTP Method 'GET' not allowed. Allowed are POST"
  }
]

If I make the method @HttpGet, it works

Have anyone any Idea why @HttpPost is not working?

enter image description here

Thanks

Best Answer

I found the problem as I make my site secure by HTTPS and was doing a request on HTTP, So the post request was discarded.

Thanks