The following steps will assist you in checking your outgoing mail settings in Apple Mail:
1. Click on the Mail menu and choose Preferences.
2. Click on the Accounts icon and select your e-mail account from the list on the left-hand side.
3. Locate the Outgoing Mail Server (SMTP); click on the outgoing server drop-down field and select Edit SMTP Server List. A new window will open, displaying all of the SMTP servers configured in Mail.
4. Select the SMTP server for your e-mail account and check the following:
- Under Account Information, find the Server Name and set it to mail.yourdomain (e.g.: mail.example.com)
- Click on the Advanced button.
- Select Use custom port and set this to 587.
- Ensure that the Use Secure Sockets Layer (SSL) box is unticked.
- Set the Authentication option to Password.
- Enter your User Name: this must be your full e-mail address (e.g.: firstname.lastname@example.org).
- Enter your Password. This is the same password that you use for your incoming mail.
5. Click OK.