clean Zen Install
no mods

Paypal Express installled and working fine ( after a change suggested by DR Byte in https://www.zen-cart.com/showthread....n-you-selected)

PaypalWPP working fine with no Cardinal Credentials added to it.

As soon as I add Cardinal Credentials I get problems. From Checkout Confirmation I am returned to Checkout Payment with 'We were not able to process your order. Please select an alternate payment method, or contact the store owner for assistance.'

I am pretty sure that the cardinal credentials are right because in their control panel I can see the request. For instance:

Lookup Date : 06/04/2015 13:33:21 EDT
Authenticate Date :
Merchant Id : [email protected]
Order Number : 8f1d01cd9b0d7eadedc28651b5e366c4
Transaction Id : FywMXlhsEFwl0N95I0j0
Credit Card : ######******####
Amount : £0.10GBP
ACS URL : https://sas.sermepa.es/sas/Secure
Bin Bypassed Flag : false
DS Response Time : 1641 ms
Enrollment Status : Y
Authentication Status :
Signature Status :
CAVV / AAV :
ECI : 01
XID : Rnl3TVhsaHNFRndsME45NUkwajA=
ErrorNo : 0
ErrorDesc :
Single Message Enabled : true
Single Message Authenticate Sent: false
AuthenticationPath: UNKNOWN
Lookup Detail:
Authenticate Detail:
So am pretty sure that communication is at least initiated.

The only logs I receive are a Paypal log that seems to end early. Like this:

Jun-04-2015 17:33:20 (1433439200)
getLineItemDetails 7 - subtotal comparisons
BEFORE line-item calcs: Array
(
[AMT] => 0.1
[ITEMAMT] => 0.1
[TAXAMT] => 0
[SHIPPINGAMT] => 0
[SHIPDISCAMT] => 0
[HANDLINGAMT] => 0
[INSURANCEAMT] => 0
)
AFTER doing line-item calcs: Array
(
[AMT] => 0.1
[ITEMAMT] => 0.1
[TAXAMT] => 0
[SHIPPINGAMT] => 0
[SHIPDISCAMT] => 0
[HANDLINGAMT] => 0
[INSURANCEAMT] => 0
[L_NUMBER0] => MSIMEXP
[L_NAME0] => Microsoft IntelliMouse Explorer [26] Model: PS/2
[L_QTY0] => 1
[L_AMT0] => 0.1
)

=================================

Jun-04-2015 17:33:20 (1433439200)
getLineItemDetails 8
checking subtotals...
Array
(
[calculated total] => 0.10
[AMT] => 0.10
[ITEMAMT] => 0.10
)

-------------------
difference: 0 (abs+rounded: 0)
=================================

Jun-04-2015 17:33:20 (1433439200)
getLineItemDetails 10
subtotals balance - okay
=================================

Jun-04-2015 17:33:20 (1433439200)
before_process - DP-1
Beginning DP mode
=================================
Any help gratefully received :-)