Yes. your ISP is blocking outgoing SMTP servers on logical port #25. So Open Mail's Preferences->Account's Tab->Select the setting "Outgoing Mail Server (SMTP):" and use the drop down to "Edit Server List ...". In the drop down select the "Advance" tab and in the "server Port" put in 587 and put a check mark in "Use Secure Sockets Layer (SSL)". Then below use "Password" and put in your .Mac name and password.
Originally Posted by rudyvanloo@mac.
To check to see if it worked select Mail's menu item Window->Connection Doctor. This will test to see if the change helps.
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