If you are unable to send Email from your Outlook then there are two possible reasons for this issue.
1) You have not done settings for Outgoing Emails
2) You have not set the correct port for SMTP
Follow below given steps to correct both of these settings:
Open Outlook and select File tab and then select "Account Settings"
Here your Email Account will be listed, Edit it and provide you Email settings here like Email ID, Password, Mail server etc
Click the button "More Settings"
Now select the second tab titled as "Outgoing Server"
Now check the option "My Outgoing sever (SMTP) requires Authentication"
Then select the fourth tab in same window named as "Advanced" and set SMTP port as 26
Save the account settings
Apply the settings and you are done with the required settings. Now you should be able to send Emails as well.