paypal integration problems

[kujojohnk]

Hi Ladies and Gentlemen, I am having problems linking my prestashop website to accept payment through paypal. everything works fine during check out until the customer is about to make the payment the following error occurs;

 

 

Please refer to logs:

• PayPal response:
  
• TIMESTAMP -> 2012-06-09T13:46:22Z
  
• L_ERRORCODE0 -> 10002
  
• L_SHORTMESSAGE0 -> Security error
  
• L_LONGMESSAGE0 -> Security header is not valid
  
• L_SEVERITYCODE0 -> Error
  
• PayPal returned error
  

I am using PS v1.4.7 and pay pal v2.8.8.1

 

Please I installed this website months ago but still can't launch. any help please.

 

kujo