Below is a lit of errors that may occurs if your store is not configured correectly.

1.  Header contains an invalid value 

This error indictaes that you are using invalid Application ID.  If you have set the configuration of the module to Production mode, you must use your own Application ID.  In order to use Paypal Adaptive module, you will need API credentials and an Application ID.  For details on how to apply for Paypal API credentials and Application ID, please visit here

2. Security header is not valid - Sandbox testing mode or production mode?

TIMESTAMP: 2014-01-29T08:27:54Z
CORRELATIONID: c93b522f88316
ACK: Failure
VERSION: 98.0
BUILD: 9285531
L_ERRORCODE0: 10002
L_SHORTMESSAGE0: Security error
L_LONGMESSAGE0: Security header is not valid
L_SEVERITYCODE0: Error

 This error usually happens when your Paypal account API credentials does not match the running mode of the module and Paypal enviornment - Sandbox testing.  If you use real Paypal account API, then you must choose "No" at configuration of "Sandbox testing". If you are using testing Paypal account API, you must choose "Yes". If you do not have Paypal sandbox account, you have to apply a Paypal sandbox account from Paypal developer network.

Also it could be possible that your Paypal API informaiton is expired or entered incorrectly.

3.  User is not allowed to perform this action 

This error occurs when you have configured the module to use "Chained Payment" mode, but you have not applied "Advanced Service" for Paypal Application ID.

When you apply for a Paypal Application ID, you are required to choose the level of service. You need to choose Advanced Service to be able to use Chained Payment.  You can only use Parallel payments if your choice of Application is for Basic Service.  Change the module to use "Parallel Payment" instead of "Chained Payment" mode should resolve this error.

4.  Invalid request parameter: email cannot be blank

This error occurs if you have not set your store's Paypal Account Email on the Agile Paypal Adaptive module configuration screen. Or, some of the sellers have not set their Paypal Account email address when a customer is trying pay that seller. Each Seller must set this option to their Paypal email address.  See below on how to set seller Payment information.

• How to set up seller payment account email - PrestaShop 1.5x

 5. Invalid request parameter: email is invalid

This error occurs if you or your sellers are using an invalid Paypal Account email addresses.  Make sure all email addresses are correct, and are linked to a Paypal account. (Either production mode or sandbox/testing mode)

6. Authentication failed.  API credentials are incorrect.

From this error message, it is obviously that your API credential are incorrect. Please make sure you have entered the correct API credentials which you created in your Paypal Account.  Please also check that your credentials are matched with your module running mode.  Do not use production credentials for sandbox/testing use, and visa versa.  Also please note, sometimes when you use Copy&Paste spaces may be included.  Please try to enter this information manually.

7.  Protocol https not supported or disabled in libcurl.