I'm receiving the following error when trying to use Paypal Expres:

We are sorry for the inconvenience. The PayPal account in this store is presently misconfigured to use mixed sandbox and live settings. We are unable to complete your transaction. Please notify the store owner so they can correct this problem. (10002)

Payment Zone
--none--
Set Order Status
Processing [2]

Set Unpaid Order Status
Pending [1]

Set Refund Order Status
Pending [1]

Express Checkout: Require Confirmed Address
No

Express Checkout: Select Cheapest Shipping Automatically
Yes

Express Checkout: Skip Payment Page
Yes

Express Checkout: Automatic Account Creation
Yes

Payment Action
Final Sale

Transaction Currency
Selected Currency

PayPal Page Style
Primary
Live or Sandbox
sandbox

Debug Mode
Off

Any Ideas/help appreciated