Code Redemption is temporarily unavailable

For the past two days I been getting a Code redemption is temporarily unavailable. Try again later error message every time I try to use my redemption code for my educational app purchases. However, my work colleague also has a Mac Pro and was able to applying his redemption code for his machine with no problem or error message. I don't know why my Mac Pro is not able to apply the code. I am running Yosemite 10.10.2. Is there a way to resolve this issue?