I was having trouble with Paypal orders automatically processing also. For past week we have had to manually process/complete many of the orders with a few going through except for the last two days nothing, no transaction logs received from Paypal. I even upgraded CubeCart to the latest version 6.1.5 with no help. Re-installed Paypal standard plugin and turned on IPN notifications on Paypal. Nothing worked but I did find in the Paypal IPN history logs that the transactions that were working had different Notification URL: Notification URL: http://www.mystore.com/index.php?_g=rm (Non-working transaction, never received back to my website) Notification URL: http://www.mystore.com/index.php?_g=rm&type=gateway&cmd=call&module=PayPal (Same on all working transactions) I upgraded my PHP version from 5.5 to 5.6 on the A2 hosting Cpanel, now running PHP version 5.6.30 and my Paypal transactions are working again. Enabling Paypal IPN notifications isn't necessary for CC6 to work but it does provide good information to review the transactions. You might look at your Paypal IPN transaction log to see if you have a similar issue or just try updating the PHP version to 5.6.30. It appears by looking at the two Notification URLs above the "&type=gateway&cmd=call&module=PayPal" info in the script to Paypal is missing so it will never be able to return the transaction data. I turned off my IPN Notifications on Paypal after updating the PHP and it still works. I hope this helps someone with similar issue.