Let me help get you down the right direction. That error usually happens because the email account is not setup correctly. Please follow the steps below to get everything up-to-date and running!
1. Choose QuickBooks, then Preferences.
2. Choose the Email icon.
3. From the Send Emails Using Section, select Custom.
4. From here you should see a list of email accounts.
5. Select the "Plus" (+) icon to add a new account.
6. Add a account name and then add settings from your email provider.
7. You can repeat this process for any other accounts that you'd like to add.
Once these steps are completed, try sending statement emails and see if your issue is resolved.
If you have any other problems moving forward, whether it be with your email address or something else. Please, don't hesitate to reach out here. Have a wonderful day.