The only information the customer gave me was saying this:

"On the Final Step, I hit 'confirm the order' and it takes me to this page - This page isn’t working

www.paypal.com didn’t send any data.
ERR_EMPTY_RESPONSE"

So by looking at that log file above, I notice a couple of things that need explaining.

I noticed that the Line Item total was $0.01 off from the calculated total. Would that cause it to fail?

I also noticed that this order was a combination of virtual and physical products, and my virtual product was accidentally configured to say:
- Yes, Skip Shipping Address##
- and Yes, Always Free Shipping##

Perhaps that combination with physical items caused a problem?

If anyone can decipher that log file above and let me know why the customer said it was failing, that would be a big help!