Hello there, @BuxtonPudding. I see that this is a duplicate post,

My colleague, @GeorgiaC already responded to your previous post about this, I'd be happy to route you to see the response. You can click the link below to see the response.

https://quickbooks.intuit.com/learn-support/en-uk/transactions/re-bounced-emails-and-de[…]-issue-whe...

If you have any additional QuickBooks-related concerns, feel free to click the REPLY button on the link that I've provided above.