RQM Proxy not getting response from DOORS

https://myDOORS/rm/views?oslc.query=true&projectURL=[Project URL]&oslc.prefix=rt=<https://myDOORS/rm/types>&oslc.select=rt:[Custom Attribute Id]

But calling this URL returns OK status with an empty response message:

https://myRQM/qm/proxy?uri=[URL from above passed through javascript's encodeURIComponent]

Can you tell if there a problem/limitation with the RQM proxy service, or what DOORS can send via proxy? Or am I doing something wrong? I do have Global Config Management enabled, and my URL does not specify the config context... but I would expect an error if DOORS can't identify it and needs it. However, maybe getting OSLC from within a DOORS widget is OK, whereas getting OSLC from RQM requires some other upfront info?

I can see that the RQM application makes plenty of proxy calls that DO work (such as /qm/proxy?uri=https://myJTS/jts/whoami), and a proxy call to DOORS when I open a requirements picker.

Thanks in advance!