I'm receiving a number of 'bounced' emails when sending out emails to clients. The clients addresses are correct. Can anyone give me any pointers on what the problem is?

Hi there, @info-lizatlancas. 

I know you've spent a lot of time on this already. I'm here to provide the reason why you're getting bounced emails when sending emails in QuickBooks Online (QBO).

Currently, the investigation related to bounced emails is still in progress. I'd recommend reaching out to our QuickBooks Support Team so that you'll be added to the list of affected users. Rest assured that you'll receive updates about the status of the issue.

In keeping with this, I'd recommend contacting our Customer Care team. They can add your account to the list of affected users. This ensures you're in the loop about the investigation's status and its fix.  You'll first have to check out our support hours to ensure we can assist you on time. Here's how:

1. Sign in to your QBO company.
2. Go to the Help (?) menu.
3. Select the Search tab.
4. Click the Contact Us button.
5. Enter a brief description of your concern in the What can we help you with? field.
6. Select Continue.
7. Choose the Chat with us option to connect. 

Additionally, I've added an article that'll guide you in personalising your sales forms in QuickBooks Online. This helps you add the info that matters most to your business: Customise Invoices, Quotes, and Sales Receipts.

Please keep me updated on how it goes in the comments below. If there's anything else you need or concerns about managing your emails and other income transactions in QBO. I'm always here to help.