gift card redemption

I purchased a gift card at a target store and I tried to redeem it but I keep getting a message that the verification code is incorrect. I have checked my code numerous times and it is correct. I followed the instructions and typed in the serial number on the gift card and I got a message that the new verification code matching the serial number was issued and to redeem it. The verification code did not change on the screen, I did not get an email giving me a new code and when I click on redeem, I get a message saying the code is incorrect. What am I missing here?