Hi DW,
The setup i mention in this other post https://doc.dynamicweb.com/forum?PID=1605&ThreadID=94855 has stopped working in DW 10.9.1, but is working in DW 10.8.0.
There no error logs in the Dynamicweb solution, but with the help of my colleague Kevin (the hardcode MVP saviour), we found these logs in the EventViewer of the environment.