Does anyone know why some invoices won't send? it"s saying email not valid but they are

Good morning, @rmhouseholdsanit.

Thanks for taking the time to reach out to the QuickBooks Community. I hope you're having a great day so far. 

Since the emails are valid, let's try some basic troubleshooting steps for this one, such as clearing the cache from your browser. 

Web browsers collect cache to save time when loading repetitive data and images. Over time these files can become outdated and corrupted, causing issues like the one with your error message. I'm including the links for all supported browsers that contain the steps to clear the cache below. 

• Firefox
• Google Chrome
• Safari for Mac
• Safari for iPad and iPhone
• Microsoft Edge

Once you clear the cache, please restart the browser so the changes can take effect. 

That should do the trick. Let me know if you continue to have issues with the error message. I'm only a reply away if you have any additional questions or concerns. Have a good one!