Might be old, but i couldnt find an answer anwyhere about the "user cancelled error" in dx11. So here is the solution that i found:
Go to OCCT settings and select none on monitoring software and then use your own monitor if you want (HWInfo, HWMonitor, Aida ..etc)
This didn't work for me. I installed Aida64 and selected it in the drop down, but if I closed the dialog and opened back up it would still be on the default and wouldn't remember my selection.
I did get it to run with directx 9 though, even still I didn't find this tool helpful for testing OC settings. At first it didn't run any graphics when I ran it with error checking turned on, gpu load and core speed remained very low, so I ran Heaven Benchmark at the same time, then slowly increased clock speed on my gpu. As I increased there were no errors being detected and eventually the card hung with no warning.
I was hoping this tool would help me find a more accurate ceiling for my GPU overclock, but it didn't really do anything.