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Try changing your outgoing mail server to the one that your ISP has provided you for SMTP.
Meaning, use the POP we provide and SMTP they provide and everything should work fine. This is because some ISP's like Earthlink, SBC and AOL block port 25, which is the port most hosts use for SMTP. You will still be able to send mail normally from example@yourdomain.com.
As of this posting date many people are writing in saying that they have not changed their ISP or any other settings, but it just started happening. More and more ISP's are blocking this port so please try this method before contacting support.
For a visual tutorial on how to change this setting, see THIS LINK, select Email from the list on the left, and watch the demo for your email software to locate this setting. Make sure you replace the SMTP (outgoing mail server) from mail.yourdomain.com to mail.yourisp.com, smtp.yourisp.com (or whatever it is they provide you) If you are not sure of their SMTP server you will need to contact your ISP's support dept. and ask them for the name or IP address of their SMTP outgoing mail server so that you can set it up in your email program like outlook express.
OPTION #2
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