Title: Error when testing invoices
Last modified: October 29, 2017

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# Error when testing invoices

 *  Resolved [cptechdesigns](https://wordpress.org/support/users/cptechdesigns/)
 * (@cptechdesigns)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/error-when-testing-invoices/)
 * The error says “Error Code: 10002; Security header is not valid” when testing
   the invoices. Once I have created the invoice and have the link to that invoice,
   it displays that error when I hit pay with PayPal on top.

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Plugin Author [SlicedInvoices](https://wordpress.org/support/users/slicedinvoices/)
 * (@slicedinvoices)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/error-when-testing-invoices/#post-9633005)
 * This error means your PayPal API keys are incorrect. Please check on the Payment
   Settings page — either there’s a typo in the keys, or you may be using Live API
   keys in Sandbox mode (or vice versa). This page on our support site may help 
   you further: [https://slicedinvoices.com/support/paypal/](https://slicedinvoices.com/support/paypal/)
 *  Thread Starter [cptechdesigns](https://wordpress.org/support/users/cptechdesigns/)
 * (@cptechdesigns)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/error-when-testing-invoices/#post-9634576)
 * Thanks, it’s working now. There’s just one little thing now that I need to know
   in case the moment comes up. If I have to, how would I or my team members issue
   a refund of any amount to our clients?
 *  Plugin Author [SlicedInvoices](https://wordpress.org/support/users/slicedinvoices/)
 * (@slicedinvoices)
 * [8 years, 7 months ago](https://wordpress.org/support/topic/error-when-testing-invoices/#post-9653712)
 * With PayPal payments you would have to login to your PayPal account and issue
   the refund from there.
 * Glad the error message is resolved, I’ll go ahead and mark this thread “resolved”,
   but if you have any other questions just let us know!
 * Cheers

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘Error when testing invoices’ is closed to new replies.

 * ![](https://ps.w.org/sliced-invoices/assets/icon.svg?rev=1314180)
 * [Sliced Invoices - WordPress Invoice Plugin](https://wordpress.org/plugins/sliced-invoices/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/sliced-invoices/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/sliced-invoices/)
 * [Active Topics](https://wordpress.org/support/plugin/sliced-invoices/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/sliced-invoices/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/sliced-invoices/reviews/)

## Tags

 * [code](https://wordpress.org/support/topic-tag/code/)

 * 3 replies
 * 2 participants
 * Last reply from: [SlicedInvoices](https://wordpress.org/support/users/slicedinvoices/)
 * Last activity: [8 years, 7 months ago](https://wordpress.org/support/topic/error-when-testing-invoices/#post-9653712)
 * Status: resolved