I  know it can be time-consuming to enter your passcode every time you email an invoice, vectorsteel, and timesawasting. Let's identify the causes and implement a resolution so you can resume your work efficiently moving forward.

It could be that your email provider needs to verify another token or a one-time passcode for each transaction or there has been a 2-Step Verification enabled. To verify this, we can check your email settings by following Step 2 in this article: Fix webmail password issues in QuickBooks Desktop.

If the issue persists, let's use another email provider that doesn't require authentication codes, which helps you avoid the passcode issue when emailing invoices to your customers.

Additionally, I've added this article for your future reference on setting up email service in QuickBooks Desktop: Set up email service.

I'll be in the Community space if you have more questions or concerns about sending your invoices in QuickBooks. Always leave a reply below, and I'll provide the necessary help.