The best way to test whether or not the SMTP connection is working is to send yourself a test email.
Once here, find the row of the email that you’d like to test, and click the more options button, and in the dropdown click, “Send Test Email”:
This will pull up a modal window where you can enter an address to send the test email to. Send it to an address that you can monitor.
Wait up to 3 minutes.
If you see the test message come in (and be sure to check your spam folder), then great, you’re all set!
If you do not see the test message come in within 3 minutes, you likely are experiencing an SMTP issue. At that point, you can click the status icon for more info: