I purchased a box copy of LR6 from a retail store (Best Buy) and when I use my redemption code to retrieve my serial number I receive a message that the code is invalid. I have entered the alpha-numeric code correctly several times.
Please use the below link to follow correct redemption steps.
Redemption code help
If that doesn't help, please contact the Adobe Customer Service : Contact Customer Care
Hope it helps.
Retrieving data ...