When I try to register my POGO, it tells me it's not a valid serial number. June 27, 2018 21:28 Updated Make sure you're using a proper POGO serial number. They have six digits starting with "21". Related articles I am replacing someone and need to register POGO in my name What is a Warning? Can I still use POGO if I don't own a smartphone? POGO Bluetooth How do I send data to the cloud?