I can no longer see when a customer opens/reads an invoice emailed to them

Hello there, angie100.

I understand how inconvenient it can be if you're unable to see the activity status of an invoice in QuickBooks Online after emailing it to your customers. I'm here to help and provide a solution to this issue.

I've replicated this on my end and confirmed how the invoice activity status works. It's possible that you or someone with admin access changed your account's Online delivery settings, which explains why you can't see the status activity of your emailed invoice, whether it's already been VIEWED by your customer or not.

To resolve this, you need to make sure that the following settings for your Online delivery is set up correctly.

Here's how:

1. Log in to your QuickBooks Online account as admin.
2. Go to the Gear ⚙️ icon, then Accounts and settings. 
3. Choose the Sales tab, then scroll down till you see the Online delivery section. 
4. Click on Edit✎.
5. Make sure PDF Attached is checked and select Online invoice under the Additional email options for invoice.
6. Hit Save, then Done.

Once done, the invoice activity status will automatically update and should be visible in your invoice list in the Sales menu.

If you want to learn more about invoice statuses, you can check out this article: Create invoices in QuickBooks Online.

I've also added this resource for future reference if you need to know how to send an email reminder to your customers about upcoming invoice due dates: Send invoice reminders automatically or manually in QuickBooks Online.

If you have any further questions or need assistance with any invoice-related concerns, please let me know. I'm here to support you. Enjoy the rest of your week.