First, you check the code and make sure it is for Ultra Violet or VUDU. Many codes are for other sites. When you buy a code do so using Paypal because they guarantee the codes. The retailers do not. You must set up an account with both and connect them. Any movie you redeem on UV should appear in your VUDU account. If you still don't see it in your VUDU account call the person who supplied the code. They should give you a new one. If from a store, call the manufacturer listed on the UV code inside the DVD box(sony, lionsgate, warner Brothers, etc.). If it still does not work there are a host of reasons and they stem from your ISP to VUDU itself. I have found that the problems are varied.