PrestaShop Tips - Paypal module security errors

Recently,following Paypal security error are frequently reported from customers.

Making new connection to ‘api-3t.sandbox.paypal.com/nvp’
Connect with CURL method sucessfull
Sending this params:
Send with CURL method sucessfull
PayPal response:
TIMESTAMP -> 2011-05-05T20:19:51Z
CORRELATIONID -> ff812e9242c7d
ACK -> Failure
VERSION -> 53.0
BUILD -> 1878974
L_ERRORCODE0 -> 10002
L_SHORTMESSAGE0 -> Security error
L_LONGMESSAGE0 -> Security header is not valid
L_SEVERITYCODE0 -> Error
PayPal returned error

There are a few cases that error happens, most cases is that configuration incorrectly because of mis-understanding of Paypal module.

The paypal module could run at two different mode:

product mode
testing mode(sandbox)

Paypal requires different account for different environment, that is you must have testing account for testing environment and real Paypal account for product mode.

Here some of the cases of mis-configuration

1. Use testing(Sanbox) account for product mode use
2. Use real paypal account for testing mode
3. Typo of username or password or API signature


Please note:
If you use copy & paste to input username/password/API signature, you may included extra white spaces when copy it.