Try 

1. Opening your QBO account on any private/incognito browser and sending the invoices again.

2. Sending a dummy invoice to your own email address

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.

This is becoming a HUGE ISSUE!!!!!! 

Quickbooks is sending emails from servers that have IP addresses that are blacklisted and they continue to use them, which is causing all of our invoices we are sending to clients to bounce by anyone who has a reasonably good spam filtering service.  We can't conduct business in this way. 

Hi There -

We are also having this same exact issue. Is there anything resolved? WE CANNOT KEEP RUNNING BUSINESS LIKE THIS!

I know this hasn't been an easy process for you, TSOM.

As of now, 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.

Here's how:

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

To ensure we can assist you on time, please see our support hours.

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.

I appreciate your understanding on this matter. Please know that we're determined to get this resolved.

This is becoming a huge issue.  We rely on QBO to automate a process, only to find when checking A/R reports that a client hasn't paid.
I have recommended QBO to my clients who are now having the same issue.
Is there at least some indication of when this is expected to be resolved?

Come on, Quickbooks, you are better than this!

Thanks for joining us here, @Margie- MGL.

I'll share some information about bounce emails. We don't have the exact time frame as to when this investigation gets resolved. If you've contacted our Support Team, you'll get an email notification once the resolution is available.

In case you need additional resources related to invoices, check out this link. It contains topics with articles to guide you along: Topics about your company's income and customers.

Please know that we're always here to help if you have follow-up questions or concerns with invoices. Just leave a comment anytime below.

My service provider has tried to resolve this issue for me. 

The only thing that he is able to establish is that QBO is blacklisted by SORBS & UCEPROTECT.

I am not Techno-savvy but maybe QB needs to check this out - it could be a simple fix.

Fingers crossed for a quick resolution to a massive problem.

An update has now been issued by Quickbooks on this - and the update is ... there is no change. They are still working on a resolution. In other words they don't know what to do?

Having said that things have subtly changed - they now don't tell you when an invoice has bounced. I'm no longer getting bounced email errors and yet my customers are reporting non-receipt.

So Quickbooks way of dealing with this appears to be simply trying to make sure its customers don't know what's really going on?

Hi @Andrew124. 

It seems this is a relevant post that my colleague @KevinC has responded to from the other thread. Please check out his answer through this link: https://quickbooks.intuit.com/learn-support/en-za/manage-customers-and-income/re-having-constant-iss....

If you have other QuickBooks related concerns, feel free to get back and comment them below. I'm always around to help. Take care always!