I appreciate you for getting back to us, jeggertz.

Let's perform some troubleshooting steps to isolate why you're unable to send forms from within QuickBooks using your Gmail account.

First, you can use a 2-step verification for Google. Here's how:

1. Turn on 2-step verification for your Google account.
2. Go to QuickBooks Edit menu and select Preferences.
3. Select Send Forms.
4. Select Web Mail and Add.
5. Fill out the Add Email Info section and select OK.
6. Click OK.

If you're already using the 2-step verification option, then you're good to follow the second step:

1. Turn off 2-step verification for your Google account.
2. Turn on less secure app access in Google. You can read the Google security standards to understand how this may affect your account.
3. Go to QuickBooks Edit menu and select Preferences.
4. Select Send Forms.
5. Select Web Mail and Add.
6. Fill out the Add Email Info section and select OK.
7. Select OK.

If the same error persists, you'll have to configure the enhanced security setting in QuickBooks. Here's an article as your guide: Gmail couldn’t sign you in from QuickBooks Desktop.

I'm just a post-away if ever you have other concerns in sending emails. Have a good one!