Is 2-factor authentication turned on for the account you're trying to use? If so, you'll need a different password than your account password.
Either way, you might find it helpful to check out the steps described in the link from your error:
With some luck those will help you to fix the issue.
A good way to avoid the trouble of configuring the user-settings and later modelreflection, template-creation and transportation and troubleshooting:
Use the marketplace Module EmailService from service.mendixcloud.com