The NPrinting On-demand add-on should be installed on the QlikView Server machine (190).
Did you check the "Before you begin" section of this page? https://help.qlik.com/en-US/nprinting/17.2/Content/On-Demand/Install-Components.htm
I have seen this requirement being skipped in the past:
- The QlikView server has been added, by the NPrinting administrator, as a trusted server in the NPrinting Web Console.
HTH - Daniel.