PayPal Express loops customer back to checkout page

• Customer goes into a circle when attempting to checkout and claims there is no error shown on any of the returned pages.
• Customer is Canadian. I am USA based.
• Customer's PP account is unverified and I have "require confirmed address" enabled in setup.
• Customer's cart only contains download products (if that matters). Some are free. Some are paid.
• I have several dozen PP debug emails, if needed.

Should the customer receive some form of error message so that they can take corrective action?

If there is an error message displayed, can I edit it to be more prominent?

Have I missed something in the setup?

ZenCart V1.3.9g upgraded from V1.3.9f which was upgraded from V1.3.8a patched
Minimal customizations

I have confirmed that this occurs when the address within the ZenCart account does not match the address within the customer's PayPal account. There is no error message that a problem exists and the customer is repeatedly taken back to the PP login page after order confirmation.

Can you zip up the logs and PM me with a link to that zip file so I can download them for analysis?
ref: http://www.zen-cart.com/forum/showthread.php?t=61199

TNX DrByte,

It will be later this afternoon before I can work on it.