Unlike NPrinting 16, there is no separate location for the On-Demand log files in NPrinting 17 plus versions.
The calls are recorded in the normal server log set - C:\programData\NPrinting\Logs
The log level
must be changed to DEBUG to view the on-demand logs, because the logs appear in the engine-dev.log
file. (The bookmark name is used for reference within the logs)
Details on how to change the log level can be found at: https://help.qlik.com/en-US/nprinting/February2019/Content/NPrinting/Troubleshooting/Troubleshooting.htm
See: Troubleshooting logs
section for the version of NPrinting Server that you are currently using since different versions NPrinting require may require different methods for enabling debug logging