Comcast network recently blocked outbound email on port 25 due to unsolicited spamming and is causing Outgoing email from Microsoft Outlook, Mozilla Thunderbird and other Pop3 programs to stop sending messages.
PROBLEM: Can't Send Outgoing Messages From Comcast Network
FIX: The fix is to change your Outgoing (SMTP) Server settings from Port 25 to Port 587
You can find this setting under
TOOLS / ACCOUNT SETTINGS...
If your using (FREE) Mozilla Thunderbird, you can find this option on the bottom of the left menu under "Outgoing Server (SMTP)".
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