Thank you for posting here in the Community, @Odin Star Industries. 

I'll ensure this gets taken care of, but first, could you tell me what error you're getting? Any information will aid us in determining the source of the problem. 

Also, unexpected issues in QuickBooks Online can be brought about by problems in the web pages. Have you tried sending the sales transactions in a private window? You can follow the outlined instructions by my colleague, Maybelle_S. 

If the same thing happens, I encourage you to contact our support team for further troubleshooting and resolution. 

If you need to send numerous invoices, go to the Send multiple invoices page. You can also send clients reminders when their invoices are past due 

For additional questions or updates about this QuickBooks Online invoicing concern, post here again. I'll be right here if you need anything else. Have a nice day!