Email Security for Apple Mail
1.Open Mail and go to Mail -> Click on Preferences.

2. Click the "Accounts" tab and click on your email account to the left.

3. Make sure the "Account Information" tab is selected. In the "User Name" box, enter your FULL email address.

4. Click on the dropdown arrow next to "Outgoing Mail Server" and select "Edit SMTP Server List."

5. Select your outgoing server from the list at the top. Click Advanced.

6. Click the "Authentication" dropdown menu, and select Password. For "User Name", enter your FULL email address. Enter your password, and click OK.

7. Click "OK", then close the "Accounts" window.