SMTP is running on all the servers. If you have a problem with sending email, please try to use your domain name (domain.com - no mail or smtp in front) as SMTP server and in your mailing software (like Outlook) go to Tools -> Email accounts... -> change -> "More settings" -> "Outgoing server" -> enable "My outgoing server requires authentication" and "Use incoming mail server login details". Note: testing may not work - save your changes and try to send an actual email.
If this did not help, please contact us for an alternative SMTP port - your ISP may be blocking default SMTP port (often they say they do not - but they actually do).
If you still can not send email after that, please user your ISP's SMTP server instead. Some ISP block third party SMTP servers now so you can use only their own.