Joomla! 1.5.26
CB 1.8
CBSubs 1.3.0 RC2

Having switched PDT (Payment Data Transfer) On for my PayPal gateway I got an error when processing a test subscription (A previous payment, with PDT off, worked fine):
"Sorry your payment has not been processed. Transaction result:FAIL Error: 4020. Please try again and notify system administrator.
No suitable basket found."

However the payment and auto-recurring subscription was processed.

I am at a loss to know how to proceed. Can I email you the notifications / IPN details so that you can advise me what to do?

In CBSubs' PayPal Gateway, I changed “PayPal Business (email or secure merchant ID)” & “PayPal Main receiver account (email) (if Business is different from your main account)” from web@nabo.org.uk to be the primary rather than the second PayPal default.
That dealt with the relevant errors shown on PayPal's IPN History.

However, when I repeated the test, both IPN messages reported Transaction Made. I had the same error message on my website on completion:
"Sorry your payment has not been processed. Transaction result:FAIL Error: 4020. Please try again and notify system administrator.
No suitable basket found."
On the CBSubs Notification Report, I had the following Notification Type: PDT notification not authenticating at payment gateway.
The Raw Result began FAIL and ended $_POST=array (
);
$transaction_info='FAIL
Error: 4020';
$PDT_RESULT=array (
0 => 'Error: 4020',
);

I don't want to post the full CBSubs Notification because I am unsure what would be insecure

Edited to add: Everything seems to have worked fine otherwise at CBSubs end: subscriptions, baskets, payments

Repeated test with Merchant Id replacing email. Checked PayPal Identity Token correct.
>>>>Edited to say PayPal Identity Token INCORRECT after further checking!!!

Same error message on return to our website from Paypal:
Sorry your payment has not been processed. Transaction result:FAIL Error: 4020. Please try again and notify system administrator.
No suitable basket found.

All seems to be correct in CBSubs, as last time: Subscriptions, Baskets, Payments

3 Notifications(as last time):
16/04/12 19:51:30 IPN: Verified for single payment (seems OK)
16/04/12 19:51:25 IPN: Verified for recurring payment(seems OK)
16/04/12 19:51:14 PDT notification not authenticating at payment gateway FAIL

Notification details:

Notification Id: 10
IP Address: ***redacted***
Notification type: PDT notification not authenticating at payment gateway
Log date: 16/04/12 19:51:14
Username: Jones91000
Full name: Nathan Graham Jones
User Id: 1000

Other sections blank except for
Test Payment Notification: 0
Payment Basket: 0

Raw Result:
FAIL
Raw data: $_GET=array (
'plugin' => 'cbpaidsubscriptions',
'cbpgacctno' => '1',
'cbppdtback' => '***redacted***',
'cbpbasket' => '5',
'result' => 'success',
'cbpid' => '***redacted***',
'tx' => '***redacted***',
'st' => 'Completed',
'amt' => '15.00',
'cc' => 'GBP',
'cm' => '5',
'item_number' => '',
'sig' => '***redacted***',
'Itemid' => '239',
'option' => 'com_comprofiler',
'task' => 'pluginclass',
);
$_POST=array (
);
$transaction_info='FAIL
Error: 4020';
$PDT_RESULT=array (
0 => 'Error: 4020',
);


Where do I go from here, please, Kyle?

I re-checked the identity token and noted that the second character was a lower case w instead of an upper case W - how that could have happened given I used cut and paste, I don't know. But it did!
Having re-pasted the PayPal Identity Token, the transaction went through AND returned me to the correct page.
Thank you for your help.