Validating endpoint URL in ASP.NET Core - Request Body is empty

Hello, I am trying to validate my endpoint URL in ASP.NET Core

But this line of code give me error:

var message = "v0:" + Request.Headers["x-zm-request-timestamp"] + ":" + JsonSerializer.Serialize(Request.Body);

The problem is the body is empty and has no value although the binding is done successfully as we can see in this image:

I detect the body here:


Can you share your complete code here?