There can be several reasons why this might happen, but the following troubleshooting methods should be able to help out quite a bit.
1) If you're using Paypal or a Debit Card make sure there's enough money in the account that you're using for your eMastered subscription.
2) If your card number or info has recently been changed make sure to change your billing info in the "My Account." section of the website. We have an explanation for how to do this in our knowledge base.
3) Trying a different device or web browser can also have an impact in some scenarios, so let us know if the issue persists when trying on a different computer / web browser as well.