Title: Checkout Error – Security Header is not valid
Last modified: July 5, 2019

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# Checkout Error – Security Header is not valid

 *  [FSFLMW](https://wordpress.org/support/users/fullmixmarketing/)
 * (@fullmixmarketing)
 * [6 years, 10 months ago](https://wordpress.org/support/topic/checkout-error-security-header-is-not-valid/)
 * We’re receiving the following error when someone selects the ‘place order’ button
   on our website when paying via the credit/debit option on our site.
 * **Security header is not valid
    (Transaction Error) something is wrong.
 * We have forced SSL in our .htaccess file
 * We have also been via [https://yourwebsite.com/wp-admin/options.php](https://yourwebsite.com/wp-admin/options.php)
   and changed the woocommerce_force_ssl_checkout option from No to Yes.
 * None of the above has worked for us. Could you help us find a solution.
 * Thanks.

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

 *  Plugin Support [mbrsolution](https://wordpress.org/support/users/mbrsolution/)
 * (@mbrsolution)
 * [6 years, 10 months ago](https://wordpress.org/support/topic/checkout-error-security-header-is-not-valid/#post-11706963)
 * Hi, do you know if you set up our plugin correctly? Are all your other plugins
   up to date? What happens if you disable our plugin? Do you still see that error
   message?
 * Can you also test one of WordPress default themes like Twenty Seventeen while
   our plugin is active? This is just for testing purposes.
 * Regards
 *  [sherkhanu](https://wordpress.org/support/users/sherkhanu/)
 * (@sherkhanu)
 * [6 years, 9 months ago](https://wordpress.org/support/topic/checkout-error-security-header-is-not-valid/#post-11743943)
 * Hi,
 * I am getting the same error on my site [https://warehouse-19.com](https://warehouse-19.com)
   
   The issue only happens when checkout form with credit card data is submitted.
   On searching the above error message a bit, it seems that it’s either because
   of wrong credentials or wrong api end points.
 * I have checked and rechecked the credentials 10x times. Not sure about the api
   endpoint.
    It will be nice if the plugin builts a log of error messages so that
   we can check it in detail.
 * Kindly help resolve the issue.
 * Thanks,
 * PS: My plugins are upto date. Error is only generated when payment is made through
   this plugin so I guess disabling or enabling it has nothing to do with the error.
 *  Plugin Support [mbrsolution](https://wordpress.org/support/users/mbrsolution/)
 * (@mbrsolution)
 * [6 years, 9 months ago](https://wordpress.org/support/topic/checkout-error-security-header-is-not-valid/#post-11746338)
 * [@sherkhanu](https://wordpress.org/support/users/sherkhanu/), can you start a
   new support thread. This helps manage one problem at a time for one user.
 * Thank you

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

The topic ‘Checkout Error – Security Header is not valid’ is closed to new replies.

 * ![](https://ps.w.org/woocommerce-paypal-pro-payment-gateway/assets/icon-128x128.
   png?rev=3474460)
 * [Payment Gateway for PayPal Pro & PayPal Checkout for WooCommerce](https://wordpress.org/plugins/woocommerce-paypal-pro-payment-gateway/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/woocommerce-paypal-pro-payment-gateway/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/woocommerce-paypal-pro-payment-gateway/)
 * [Active Topics](https://wordpress.org/support/plugin/woocommerce-paypal-pro-payment-gateway/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/woocommerce-paypal-pro-payment-gateway/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/woocommerce-paypal-pro-payment-gateway/reviews/)

 * 3 replies
 * 3 participants
 * Last reply from: [mbrsolution](https://wordpress.org/support/users/mbrsolution/)
 * Last activity: [6 years, 9 months ago](https://wordpress.org/support/topic/checkout-error-security-header-is-not-valid/#post-11746338)
 * Status: not resolved