HDCP errors happen when there is a problem with the physical connection or communication between your streaming device and TV. Often, it's a simple matter of reconnecting the HDMI cable:
Unplug both ends of the HDMI cable.
Turn off or unplug power from the TV and streaming device.
Reconnect both ends of the HDMI cable.
Turn on or replug power to the TV and streaming device.
If that doesn't do the trick, try these additional suggestions:
Use a different HDMI input on your TV.
Use a different HDMI cable.