These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.
In addition to using the right ports, you also need to select STARTTLS as the security method and “normal password” for the auth method. The full email address is used for the username. See the VestaCP docs for connecting to a mail client here.
The developer cloud
Scale up as you grow — whether you're running one virtual machine or ten thousand.
From GPU-powered inference and Kubernetes to managed databases and storage, get everything you need to build, scale, and deploy intelligent applications.