Have you tried removing the current driver and reinstalling?
Is there some sort of .INF/driver to install on the PC for the receiver? It could be that the amd drivers don't know what it's connecting too, so it fails the HDCP test.
Yup, spent half a day going back to 640x480 and tried every driver that had worked before.
There's no .INF or driver for the receiver. The BD Advisor HDCP test shows both the receiver and projector as a Pass. Only the graphics card driver is a Fail.
Problem solved. It seems that one of the Microsoft updates broke the Media Feature Pack. If you get the same problem with Windows 10N or K, install these KBs in this order:
The second one is for the Anniversary Update of Win10 so will only install if you've done that update.
These should fix "This content is protected" errors in Amazon Video and iTunes should allow you to rent/play HD content.