Like I said, I did not see any attempts from PayPal in the logs you sent me. So one of three things.
1) They did not show cause there was no action from PayPal at the time.
2) A issue with PayPal.
3) A issue with your server.
IMO it is number 3, so you would need to contact your host to have then figure out what the issue is. Or perhaps #2, then you would need to contact PayPal.