Internal Server Error status 500 when doing a POST with HttpClient

Question

_{Sunday, October 15, 2017 6:35 AM}

I have Global action in CRM. It have one input json string parameter. This is call for sending request

and my method SendAsJsonAsync looks like this

When I execute this I am getting this exception

All replies (3)

_{Sunday, October 15, 2017 2:13 PM}

Put a breakpoint in your API endpoint and trace to see where the error is thrown.

_{Sunday, October 15, 2017 4:41 PM}

You could also read the response's Content to see if it contains the Stack Trace.

_{Sunday, October 15, 2017 5:03 PM}

I think path should not be here:

"api/data/v8.1/" is already defined in BaseAddress.

Update: