What is the email limit when sending invoices?

I am trying to send my first batch of invoices by email. I have sent 5 items successfully. On item 6, I am getting an error dialog that says "You've reached your email limit. You can download the PDF, send it directly through your own email account or try again tomorrow." This also applies if I try to send item 7 instead of item 6, so it doesn't appear to be specific to any one item.
It is now tomorrow (from when I first hit this issue) and the error is still there. That is, the limit does not appear to have reset. Is this what is supposed to happen?
Can someone point me to where this is explained in the documentation, so that I can understand what this limit is about?

I particularly want the ease of use of sending invoices from within QBO or whatever I use to create them. And given that the incremental cost to QBO/Intuit of sending an email is near to zero, a limit of 5 emails(!) seems a little bit cheeky. I note that the limit is not stated in the error message (just that I've apparently reached it) nor is there a reference to where to find out more.

Can anyone shed light on this please?

FYI, I have already tried clearing my browser cache. I am running up to date Chrome on up to date Win11.