Have you seen this error message when trying to watch something on Roku?
Go to Roku settings and select Display type.
Select 4k30Hz TV. Your screen may go black for a few seconds while the setting is being updated.
When an image is shown, select the button that says Yes, I can see it, you will be returned to the display menu and the HDCP error should be resolved.
If you receive a message indicating your TV does not support a display type, you can still select the display type and try it anyway.