HTTP POST response with empty data problem

Job ID: 33121910

Budget: $10 – $30 USD

Hello, I am trying to send information to the printer via link "http://www.posprinterdriver.com/api/v1/api/sendDataToPrinter?linkcode=NJPPYB&data=testdata" but the response shows empty data. Here is documentation for the HTTP POST: https://github.com/solyarisoftware/posprinterdriver