Hello,
If you are using MAPI, go to your outlook settings and make sure everything is setup correctly and that you have access to your email account through it, if you do make sure you have enabled the ¨Allow Less Secure Apps¨ option and then test again.
Hope that helps, if not I would suggest you contact NCH Support for assitance. You can create a support ticket through the link below:
https://www.nch.com.au/support/index.html 
Good luck!