Free HDMI Extender incorrect SN error

Hello Burn61 

Thanks for posting here in the Community.

When inputting the serial number in the form, ensure to put zeros instead of the letter O. Please note as well that the numbers at the back of your Roku stick are referred to as the Device ID.  To know your device's exact serial number, navigate to Settings > System > About.

I hope this helps!

All the best,
Kariza