If you UNCHECK the incoming mail "requires SSL" flag, and CHECK the outgoing "requires SSL" flag, this will fix this issue.
Also make sure your email server is mail.<yourdomain> and NOT serverX.domainsunder.ca, so for example if your domain name is joesgarage.ca, then your mail server will be mail.joesgarage.ca
Outgoing port should always be 587.
Incoming port should be 143 for IMAP and 110 for POP type email.
Incoming username should be <name>+<yourdomain>, so if the email address is joe@joesgarage.com then the incoming username should be joe+joesgarage.com
Outgoing usernames are just the email address.
If this is referring to error #0x800CCC78 in Outlook Express...
If you are using Outlook Express (OE), Outlook, or Windows Mail, this error can sometimes be generated by leaving the "My server requires authentication" checkbox unchecked. You may need to try checking off this checkbox.
Use the below examples to find this checkbox:
1. Outlook 2000
Go to Tools > Services (or Tools > Accounts, if Services is not listed). Select your Internet E-Mail Account and press “Properties.” Go to the “Servers” tab, and check “My server requires authentication” under Outgoing Mail Server. Press “Settings,” select “Use same settings as my incoming mail server,” then press “OK” three times to save the changes & return to Outlook. Finally, restart your computer.
2. Outlook 2002 & 2003
Go to Tools > E-Mail Accounts. Select “View or change existing e-mail accounts” and press “Next.” Select your Intermedia.NET POP/SMTP account and press “Change.” Press “More Settings.” Go to the “Outgoing Server” tab, and check “My outgoing server (SMTP) requires authentication.” Select “Use same settings as my incoming mail server” and press “OK.” Press “Next,” then press “Finish” to confirm your changes and return to Outlook. Finally, restart your computer.
3. Outlook Express
Go to Tools > Accounts. Select the “Mail” tab. Select your Intermedia.NET account and press “Properties.” Go to the “Servers” tab, and check “My server requires authentication” under Outgoing Mail Server. Press “Settings,” select “Use same settings as my incoming mail server,” then press “OK” twice times to save the changes, then press “Close” to return to Outlook Express. Finally, restart your computer.