Mozilla Setup
Step 2

Step 2:
Configure the Outgoing Server
Multiple email accounts can use the same Outgoing SMTP Server.  Therefore, SMTP Servers are created separately from email accounts.  In the Account Settings Dialog, in the left pane, select Outgoing Server (SMTP) from the bottom of the list.  There may be an entry in the resulting list that was created when you entered your account details.  Either edit that entry or add a new entry.  Must look as shown on the right.  Press OK.