Attempt to send test email in SolusVM fails: SMTP connect() failed.

Symptoms 

Attempt to send test email in SolusVM fails:

SVM_ERROR: Error!
Email not sent
SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

Cause

SMTP Mail Type is selected in Dashboard > Configuration > General Settings > Mail, however SMTP settings set incorrectly.

Resolution

To get more verbose output, enable debug flag on SolusVM Master server:

# touch /usr/local/solusvm/data/smtp-debug

Try to send test email once again and check for more detailed error message.

Verify that SMTP settings are set correctly, like hostname, port, user and password.