My TD Bank Gift Card keeps on getting rejected on Sephora?

Okay, so I'm ordering on Sephora and I have a TD Bank Gift Card. It has about $35 on it, and my order is less than 20, so I know it has enough. When I put it into the credit card option, I put in Visa (it says Visa on my card) and the 16 digit number and the expiration, but it is not accepting it. I don't know what to do!