Whither thou M454dw serial number?

[LadyLucee]

I've searched my Color LaserJet Pro M454dw printer high & low... on both sides, the top, bottom, inside the paper tray--everywhere I can think of or see--I see the model # but no serial number. When I turn the printer on & look @ the display, a "serial number" is displayed but when I copy/paste that # in HP support, it says it does not exist/no device found. The HP print & Scan Doctor software also displays the same serial # that appears on the printer display but again, HP support says that # is invalid/does not exist/no device found. What the what/where (on the printer itself) is 1) the serial # and 2) if the serial # displayed on the printer & in the HP Print & Scan Doctor software is truly invalid, where might I find the CORRECT serial number? P.S. The printer was purchased in 2020 from HP.com.

[Valsimot]

The serial number is just fine, it's a 10 digit starting with two letters that represent country of origin 

CN China, TH Thailand, MY Malaysia  for example CN12345678  if the HP support sometimes can get wrong and doesn't recognize valid serial number.