I have the exact same problem even though with different GPU (Gigabyte R9 280X) and Monitor (Samsung T260)
I know that all the two are HDCP compliant as I have them by many years now and they worked flawlessly back when I had Windows 7.
Now I have upgraded my rig with a brand new Ryzen 1600X paired with Windows 10 1703 and HDCP is no more active.
I found a way to temporary restore the HDCP capability by toggling the GPU scaling flag under Display,
the display goes black for a second and after it lit back on the BDAdvisor pass the HDCP test, see results below
Hope this help you,
for me this is not a permanet solution but it's better than nothing,
any times I restart my PC the issue return no matter how the switch is saved
before the toggle
after the toggle