Hello Douglas!
Sorry for the 4 hour delay, I was on the road today.
This is means one of the following issues:
1. You are using email in configuration that is not the main paypal email associated with the account.
2. QuickSell can not connect to PayPal to verify the transaction due to curl/allow_url_fopen to be turned off.
This is what comes to my mind now.
If you can share login information for the administration panel, I can login and make sure it's all working.
I guarantee it will be working within hours. Here is 20:30 PM now but I will be available for at least three more hours today, and I would love to help.
Thanks!