Thank you for bringing this to our attention. I want to make sure you'll be able to send your invoices successfully.
We haven't received similar cases about this error when sending invoices. To isolate this, let's try performing some basic troubleshooting steps to better isolate this issue. Try using a private window to see if you'll get the same error message.
Re: Invoices won't send: Error "Oops, something went wrong. Maybe try again later."
If you've followed the steps provided by Charies_M and gotten the same error, you can try to send the invoice via the mobile app. If it's still the same, please contact our Phone Support Team using the steps above. We'll help you investigate this issue further.
Please feel free to reach out to us if you need more help with QuickBooks. Thanks.