c# – gRPC – JsonTranscoding – IOException: Unable to read data from the transport connection

I implemented JsonTranscoding
in my simple gRPC
application. I’ve a POST
api. When I test my POST
api using swagger, I could call it; but when I test it using Postman or
HttpClient (Acually calling api using code) I get two below exception:

IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine.

and also:

SocketException: An established connection was aborted by the software in your host machine.

*** I have no firewall on my local machine.**