Below are some general troubleshooting tips that you may wish to follow when your email appears not to be functioning properly. If the issue you are experiencing is similar to this example, it is best to give each of the steps listed below a try, since many email clients are anything but clear with their error messages.
Cannot connect when sending email onlyIn your email client settings, try changing the SMTP port to 2525 instead of the default port 25. Many ISPs block the default port 25 for other SMTP servers, and this is a rather common issue.
I can connect to send outgoing mail, but it still fails to send
Check to make sure you have SMTP Authentication enabled in your email client, which is required by the server in order to send mail. Some ISP's require that you authenticate yourself to their server and use only their smtp server and not your webhost when sending mail.
What is the size of the email you are trying to send? Our servers currently limit outgoing messages to 10MB, however when an email is sent with an attachment - it is encoded, the encoding can raise the size of an email quite a bit. Generally speaking, a 7MB attachment may approach the 10MB limit after encoding.
How many recipients are there for the email being sent? If an email being sent is of mailing-list size, it is generally best to use mailing list software such as MailMan to send the email in batches.
