I was gifted a Blacksmith shader code and I scrapped off the back part to redeem the code.
I tried typing and redeeming it and I says "Error - Invalid Code (2000)". Tried again and said "You have reached your maximum failed attempts for today, and must wait until tomorrow to try more tokens. (2004)".
What the hell.
There is a limit on how many attempts you have per day to enter in a 9-digit code on the Bungie.net code redemption portal page. This is to keep users from spamming random codes in hopes of finding a valid one.
Also, Bungie does not replace any used or invalid codes you have. If your code is expired/invalid/used, there is nothing Bungie can do to help.