Step 1
First open the Mail preferences by clicking on “Mail” in the upper left corner (by the Apple Menu) and then select “Preferences”.
Step 2
Next you will need to choose the account you want to edit from the list on the left (you may only have one and it will be selected by default).
- Click on the “Accounts” icon at the top of the window.
- Choose the “Account Information” tab.
- At the bottom of this window will be the “Outgoing Mail Server” drop down menu.
Step 3
Click on the drop down menu and select “Edit SMTP Server List…”
Step 4
At the top of this window will be the available outgoing mail servers.
- Note that there may only be one server listed. Make sure to select the correct one for the account you wish to edit if there are multiple.
- Change the radio button at the bottom so that “Use Custom Port” is selected.
- Enter the port number that your ISP has suggested for use.
- Make any other changes recommended by your service provider for use with the custom port.
Step 5
Click OK
Step 6
Click “Save Changes” if prompted when closing the Preferences window or when selecting another account to make changes to.