I am using version 1.3.8a and have noticed a sporadic issue logs where users reach the checkout_success page, go off to Paypal and then, when they finally hit that payment button, they return to a "your session has timed out" page.

No payment is taken or received, and various additional attempts have the same result. It happens on both IE8 and Mac OSX 10_4_11 so far. I have been unable to reproduce it.

I searched around and, although I found a couple of threads relatingto paypal express with the same issue, no solution was forthcoming.

Does anyone have any ideas on how to go about rectifying this problem?

Thank you in advance,

GG