We are implementing a Joomla! site with CBSubs for subscriptions for one of our clients, and taking a subscription paying by Paypal is not working. I'm gonna go and be as complete as possible here, sorry if this includes irrelevant info.

MY SITUATION/SETUP
=============

Joomla version: 2.5.
CBSubs version: 3.0.0.

We are using the subscription mainly for selling access to individual articles (which contain a video lesson).

We created a business paypal account, and set up the paypal gateway in CBSubs with the following configuration:

Paypal account: screenshot [REMOVED]
Paypal API credentials: nothing, just left empty
Paypal specific settings: [REMOVED]

Note that the paypal instructions in CB Subs are a bit out of date, paypal organizes its settings in the backend differently (for example PDT is under 'profile' > 'selling tools' > 'website preferences' which is not how it's explained in the CBSubs backend).

However, I think I did manage to find and configure all of the settings mentioned:
- IPN is enabled: [REMOVED]
- Auto Return and Payment Data Transfer are both set to ON (and the 'identity token' in the settings is filled in in the CBSubs section) [REMOVED]
- Payments in foreign currencies:

AHA,maybe it's because we are working in dollars not EUROs??? The payment receiving preferences of paypal state: 'Note: If you are using IPN, you must update your scripts to handle payments in currencies other than U.S. Dollars. Learn More'.

Did you do this???? Maybe y'all are assuming USD somewhere as the vendors currency?

Still in 'payment receiving preferences' (linked to by 'block payments' - ok so it's fucking PayPal that makes its navigation impossible) the 'Block accidental payments' was set to YES, but since it says: 'You may prevent accidental payments by blocking duplicate invoice IDs' this sounds related to my problem. Allow me to set it to NO... NOPE, still doesn't work.

THE PROBLEM/STEPS
=============

In my Joomla site, I go to a protected article (with the stuff below the 'read more...' protected, as documented in the CB Subs documentation). I then proceed to buy a subscription for access, and it sends me to paypal as expected. Also, in the paypal site, I can log in and click 'pay now', after which I would think it pays and returns me to my Joomla! site, subscription now activated.

Instead it shows this:

"We are sorry, we are experiencing temporary difficulties. Please try again later. If this error occurred while making a payment, avoid duplicate payments by checking your Account Overview before resending a payment.

For some browsers, this problem can be resolved by clearing or deleting cookies.

Message 3514"

Screenshot: grab.by/nRXy.

Note that I DID clear cookies as they suggest, but still get the same error.

Thanks for any suggestions fellows!