The error concerns the display link
Roku associates an HDCP Error Detected message or purple screen with the HDMI content-protection relationship among the player, TV and any receiver, switch or soundbar. A visible Home Screen does not prove every protected playback mode is supported.
Identify the full route before replacing the programme. A 4K or HDR route can require the relevant HDCP 2.2 support throughout the connected equipment.
Use the documented physical checks
Follow Roku’s current power and HDMI reconnection sequence, keeping connectors secure. If the issue remains, Roku documents comparing another supported input or cable and a direct player-to-TV route where an intermediary is involved.
Keep the same item for the comparison. A direct route working narrows the investigation to the changed chain; it does not alone prove a receiver or switch is defective.
Preserve the protection requirement
Review the exact equipment specifications for the desired mode. Use a supported route rather than attempting to defeat content protection. Successful ordinary desktop or menu output is not an exemption from the programme’s playback requirements.
For support, report the exact error, requested mode, equipment order and the comparison that changed it. This page contains no bypass instructions or claim that a particular protected programme has been tested.
Questions answered
Does bypassing a receiver during a test bypass protection?
No. A direct supported TV comparison still uses the required protected HDMI route.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.