HP not recognizing serial number

[RobBob22]

I am attempting to register my printer to get support with a battery issue, but HP does not recognize the serial number and displays an error of "please enter a valid serial number" after each attempt. 

The issue that I am trying to resolve (asides from the serial number not being recognized) is the battery does not hold its charge and will fully discharge in-between uses. 

[RobBob22 · Accepted solution]

I was able to figure out the serial number issue. I was using the serial number found through the display on the unit. After taking the battery out, I found the actual serial number behind the battery. It matched what was displayed on the onboard screen, but had several digits missing from the end. The shortened serial number was accepted!