If you are traveling and using your computer, you may experience difficulty sending email using a connection service other than Create Hosting. For example, a hotel's Internet service or connecting at a Starbucks Coffee Company's wireless service. Some connection services also block the standard port for sending email, SMTP Port 25.
Working around this issue requires changing the SMTP Port 25 to Port 587.
Please note that once this change has been made you will NOT need to change it back. These settings will work accessing your email from anywhere.
This document explains how to enable universal email access using SMTP AUTH in Mail.appfor Mac.
Enabling (SMTP AUTH)
- Open Mail.app.
- Go to Mail > Preferences
- Click Accounts > Account Information
- Under Account Information look for Outgoing Mail Server (SMTP).
- Click on the drop down arrow and select Edit Server List...
- Select the existing SMTP server for your domain.
- Click Advanced and change the server port to "Use Custom Port" and enter 587.
- From the Authentication drop down, select Password
- Fill in your Username (e.g. firstname.lastname@example.org) and Password
- Click the Test Account Settings button to set the new settings.
- Click OK and then close the preferences window.
- Click Next then Finish.
- Save the changes, and try sending mail again
For the full Mail.app setup instructions, please refer to the following:
How to Set Up Mail using Apple Mail on a Mac