Do you use QuickFile’s default email set up (e.g. you’re not using your own SMTP server)?
We do track bounces, but you wouldn’t receive an error as such as this isn’t known until the email is returned to us.
You can check for bounces by viewing the client in question:
Or providing you have a Power User Subscription and you’re the main administrator, there is an email report which will show you whether an email has been sent, opened, blocked (previously bounced back) or failed due to an invalid format. This can be found by going to Account Settings >> All Settings >> Sent Email Log.
Hope that helps