Hi danny-towie-com,

I think I might have an idea as to why this is happening.

Most of the time, it is the receivers email inbox settings that might be unintentionally blocking the emails from coming through.

With the customers that are not receiving the emails, could you please make sure that they have quickbooks@notification.intuit.com listed as a safe sender.

Sometimes by default, their email settings will block certain senders from sending emails to their inbox.

After they have done this, give it another try and see if it goes through this time.

Let us know how it goes.

Kristian.