Why isnt my invoice sending to my clients email?

Good afternoon Bunjymen,

Thanks for turning to the QuickBooks Community for support. It's important that your customers receive their invoices in order to know how much they owe you. I can provide some information about invoices not being sent.

This is a known issue in QuickBooks Online at the moment. I recommend reaching out to the support outside of the Community. They'll be able to verify your account details in a secure setting, as well as view you screen to better assist you. They'll also be able to attach your account to the list of affected accounts. Once your account is attached, you will receive an email as soon as the issue is resolved. You can reach them by using one of these methods:

Schedule a Callback or start a Chat: click (?)Help in the upper right > type and enter "Contact support" into the QB Assistant > click Contact Us > explain your situation > click Let's Talk > choose Get a callback or Start a Chat.
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If you have any other questions, feel free to reach out here.