This article applies email accounts that don't use SSLs for Outlook.
When setting up your email account select "More Settings" > "Outgoing Server".
Make sure that:
"My outgoing server (SMTP) requires authentication" is ticked
"Use same settings as my incoming mail server" is selected.
After the above options have been enabled goto "Advanced".
Incoming Server: "Use the following type of encrypted connection: None"
Outgoing server: "Use the following type of encrypted connection: None"
Please see below screenshots for further help.