Hi Intrinsicreef,

Let's ensure that we've entered a valid email address before sending invoices.

If its correct, you can run some steps to identify isolate if you're having browser-related issues.

 To start with, try opening QuickBooks on a private window. This is the safest place to tell if you're experiencing some browser-related issues. I've added these shortcut keys to open one:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

If you're able to edit it from there, you can go back to a regular browser and clear the cache. Cache are previously visited sites. Once these gets piled up, you'll be encountering browser issues.

 You can also use a different browser like Google Chrome, Mozilla Firefox, Safari, or Microsoft Edge.

I've also added this reference for more information in managing invoices: Manage invoices in QuickBooks Online.

There you have it. Let me know if you need help in preparing taxes. I've got your back!