Every once in a while, I get a customer whose order number is never assigned. This creates a good deal of havoc for me as I use QBI to download my orders into Quickbooks and that means I miss sales being downloaded into my income tax information unless I am very vigilant.

I do get notice of the sale from PayPal, and I do get a PayPal receipt which comes into my inbox.

The latest one was a customer who had mismatched shipping and billing addresses, alas, that had nothing to do with the fact that she was not assigned an order number in Zen Cart.

What is causing Zen Cart to skip over customers? There was a gap in the numbering, I went from order number 1685 to 1687 and she was 1686 and that number was assigned in the Zen Cart when I looked in admin but it didn't get sent to my inbox along with the PayPal receipt.

I have gotten one instance where a customer tried to buy from me and the cart didn't put her through to PayPal to complete the order. She ended up paying strictly through PayPal without Zen Cart.

Please tell me what is causing this and what I can do to fix it. Thanks.