Email not sending

I wasn’t having problems with my email before, as it was set to @sweetheartevents.ca, but no longer is working. I’ve tried lots of SMTP options with plugins and the settings but nothing seems to be working. Latest is this:
CLIENT -> SMTP: EHLO http://www.sweetheartevents.ca CLIENT -> SMTP: AUTH LOGIN SMTP -> ERROR: AUTH command failed: 504 5.3.3 AUTH mechanism LOGIN not available CLIENT -> SMTP: QUIT SMTP connect() failed. Mailer Error Mail: SMTP connect() failed.

A few screenshots of my options:
http://grab.by/D53A
http://grab.by/D53C

thanks and much appreciated! 🙂

https://wordpress.org/plugins/contact-form-manager/