Invoices I have sent are still saying Not Sent. This has only just started to happen…

Let me help you resolve the invoice status in QuickBooks, @clairebighamchil.

You're in the right place for an answer. Checking the invoice email status is dominant, so we can tell whether our customers have received or viewed the transactions.

To help isolate this issue, ensure the customer's email address is correct. Once confirmed and the problem remains, I suggest you do this trick. This way, both the recipient's mail server and QuickBooks will refresh.

Proceed with the following steps:

1. Go to the Sales tab and select Customers. 
2. Click the client name and choose the Edit button. 
3. Enter a dummy email, then save it and resend the invoices. 
4. Go back to the customer's profile and change the email to the correct one. 
5. Send it again to verify if it's performing well. 

If the status is still not updating, I'd recommend doing browser troubleshooting steps. 

Use the hotkeys below:

• Ctrl + Shift + N (Google Chrome)
• Ctrl + Shift + P (Firefox)
•  Control + Option + P (Safari)
•  Ctrl + Shift + P (Microsoft Edge)

Once logged in, review the status. If it shows Sent, please return to your regular browser and press the CTRL+ Shift and Delete keys on the keyboard to clear the cache.

Additionally, don't forget to record and deposit the payment after your customers pay you. 

Furthermore, check out these articles below on how to create recurring invoices and notify customers about upcoming invoice due dates: 

• Send invoice reminders automatically or manually in QuickBooks.
• Create recurring transactions in QuickBooks Online

This thread is still open if you have more questions about your invoices or other transactions in QuickBooks Online. I'll do my best to help you out. Take care.