I can see the urgency of resolving your concern, Atul4.

We’ll have to review your Sales settings to determine the cause of the bounced emails. To ensure the safety of your account, I recommend contacting our QuickBooks Online (QBO) Support Team again.

If you have the case number handy, provide it to our specialists to speed up the process. This way, they can perform the troubleshooting steps from where the previous one left off. Also, they’ll assist you through the process of how to apply the permanent fix. Then ensure you’ll no longer encounter bounced emails and purchase orders.

To reach them:

1. Go to the Help icon at the top to select the Contact Us link.
2. Enter a brief description of your concern in the field box and click the Continue button to see the list of support options.
3. Then choose Chat to start a conversation or Callback to speak with an agent.

I’m adding some links below for additional resources. These articles will guide you on how to troubleshoot email delivery issues. They’re from another region, but the solutions also apply to the UK version.

• How to view list of bounced emails with delivery errors
• Delivery Errors when trying to email a sales form

Additionally, you can bookmark this link in your browser for future reference. It outlines the steps to resolve when customers are unable to receive your emails.

Reach out to me again if you have additional concerns about emailing invoices and purchase orders. I’ll get back to make sure this is taken care of for you. Have a good one.