I can see that you did everything you could to fix the issue, @christina-bumpto, and I appreciate you for that.
Aside from confirming the correct email address being entered, another possible reason is that there might be a temporary issue with the recipient's email server. To verify, ask your customer if there are any issues with their email provider. This is to check if there system blocked any incoming emails from QuickBooks Online (QBO).
If everything's fine on their end, your browser might be causing the problem. With this, let's open your QBO account using a private (incognito) window if you haven't done it yet. This helps isolate the issue since it doesn't store data in the cache. To save time, utilize these keyboard shortcuts:
Once logged in, send your invoices again. If it works without issues, you can then return to your regular browsing history and clear its cache. Otherwise, use other supported browsers for alternatives.
After the invoices are sent, learn how to receive and record invoice payments if the customer paid for them.
In case you want to personalise and add specific info to your sales forms, check out this link: Customise invoices, estimates, and sales receipts in QuickBooks Online.
I'm all ears if you have any follow-up questions about sending invoices in QuickBooks. Simply leave a reply below and I'll surely get back.
You have clicked a link to a site outside of the QuickBooks or ProFile Communities. By clicking "Continue", you will leave the community and be taken to that site instead.