Mc6000mk2 registration and serial

I would like to know how to register my mc6000mk2 on my user profile of products. It does not want to accept my serial number. Have had the product for more than 2 years now but never worried about registering it.

How do i get arround the serial not being accepted… I bought it in 2019 but stored it for half a year when i worked abroad… any help will be great…

Also have the period expired to get the serato dj pro licence…