Earlier today one of our redundant email servers had a glitch preventing it from sending notification and thank-you emails, so our system began to have a backlog of delayed emails as our other servers worked to take up the slack. The problem has now been resolved, and any delayed emails for affected sales made during this time are now being sent out as we catch up with the backlog.
If you are concerned that any buyers who made purchases during this time did not get their email, you can use your Seller Admin > "Re-activate expired links and Re-send 'Thank You' Email" function to send that buyer another copy of the email we generated for their specific transaction.
We do apologize for the inconvenience and are continuing to investigate the cause of the glitch, so we can avoid this sort of issue in the future.