Hi izatowel,
Since you have verified that the email settings are correct and the email isn't blacklisted, it is concerning that the setup, which previously worked, is now experiencing issues. To resolve this, you will need to reach out to our support team directly. They can check the affected email addresses to ensure there are no underlying issues on our end. You can contact our support team via Live Chat through the virtual assistant MOCA or raise a support ticket via myaccouunt.myob.com.
Cheers,
Princess