I see that this has been a recurring issue on your end for the past 2 weeks and is affecting your daily invoice tasks, @frontlinetouchup. On top of that, I appreciate you for performing the troubleshooting steps to fix it before posting here.
With that in mind, I recommend contacting QuickBooks Online (QBO) Live Support Team to further see the situation of your QBO application, and why it displays a blank screen when sending invoices. Once they determine the root cause of this, they can provide you with the resolution for it.
In the meantime, you can log in to your account using a web browser and send your invoices there.
Let me know if you have additional questions about sending invoices by leaving a reply below.
