emails do not leave my outbox

I have my emails piling up in the outbox, with no apparent solution! I have restarted the program, and rebooted the machine - the error message that says connection to me webmail client failed offers a link to open account settings, and the diagnostic shows IMAP OK, SMTP server not responding. When I click on Fix, it sends me a mail saying it works, but the messages don’t leave the outbox!
Please help!

you have apparently incorrect settings or your SMTP server is not responding. In order to find the exact cause of the issue please enable SMTP logging for the particular account and restart eM Client. Then try to send an email and send us the logs using the same logging settings window (Tools - Settings - Advanced). Thank you.