To resolve the issue of being unable to send QuickBooks emails through Outlook, start by ensuring both QuickBooks and Outlook are updated to their latest versions. Next, verify the email settings in QuickBooks by navigating to Edit > Preferences > Send Forms. Make sure to run both applications as administrator to ensure proper permissions. Additionally, reconfigure the email integration by re-establishing your email preferences in QuickBooks. If the problem persists, use the Microsoft Office repair tool to fix any underlying issues with Outlook.