Error: Security Header is Not Valid 10002 (PayPal)
Error Message: 10002 Security header is not valid.
Cause: This error indicates an issue with the login information you are using for your PayPal connection. It is usually seen with PayPal Website Payments Standard or Pro.
Resolution: Remove your credentials, then re-enter them. If you copied and pasted the data, make sure there are no spaces before or after the information. We recommend first pasting them into a text editing program such as Notepad or TextEdit to ensure this.
Note: Make sure that you are not in test mode on either this page or within your PayPal account.