Cannot add an invoice says my request cannot be completed at this time

I’m here to help so you can add an invoice without delay, @griffoandevans.

In most cases, browser-related problems are the reason why users encounter unexpected behaviors in QuickBooks. Please know that once the browser's cached files have issues, QuickBooks functionalities may get affected. You can perform some troubleshooting steps to get this resolved.

First, open your QuickBooks Online account in a private or incognito window for testing. You can use these shortcuts keys below for quick navigation:
 

• Google Chrome: Ctrl + Shift + N
• Safari 11 or newer: ⌘ + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P

Once logged in, try to add an invoice. If you’re able to do it, get back to your regular browser and clear its cache. Doing this helps the program to run better. You can also use other supported browsers as an alternative.

If you'd like to add specific information to your invoices, check out this article for complete instructions: Customise invoices, estimates, and sales receipts in QuickBooks Online.

Moreover, QuickBooks offers ways to create a template for regular transactions and make customers' payments organized and connected from start to finish. For more details, see these resources:
 

• Create recurring transactions in QuickBooks Online
• Set up and send progress invoices in QuickBooks Online

I’ll be here to help if you have any other questions or concerns besides adding an invoice. Always take care!