I appreciate you for bringing this matter to our attention, @beecroft1. I'll provide the reason why you're getting bounced emails when sending invoices in QuickBooks Online (QBO) and guide you on the actions you need to take to resolve the issue.

Our record shows that for the time being, we have an ongoing investigation about bounced emails when sending invoices or reminders to customers in QBO. Rest assured that this issue is being taken care of with utmost urgency. Hopefully, you can send your invoices in no time.

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 can provide the INV-70915 as your reference. 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. 

Also, you may want to check out one of our Help pages as your reference if you need assistance in managing, organising, customising, and sending invoices in QBO: Invoices and Payments Help for QuickBooks Online.

Please keep me updated on how it goes in the comments below. If there's anything else you need or concerns about managing invoices and other income transactions in QBO, I'll gladly help. Take care, and have a great day, @beecroft1.