How to Consume Web Service in ABAP by passing JSON input values

Hi Experts,

I am trying to consume a web service in SAP ABAP by passing input parameters in JSON format.

The format is as below,

{ "fieldone"="value1", "fieldtwo":"value2", "fieldthree":"value3" }

The Content-Type is being set as application/json

I am using the below method to pass the input values where i_form_fields refers to an internal table containing the above data in name pair combination.

lo_client->request->set_form_fields( i_form_fields )

I am getting the error 502 - Web server received an invalid response while acting as a gateway or proxy server.

Can you please help me out in this issue.

Thanks in Advance.