Often this can occur if you're using a laptop through a non-supported provider like AOL or MSN. The best solution in this case is to use webmail (http://mail.yourdomain.com) to check your mail while on the road.
Another cause could be that you do not have your mail client set to "This server requires authentication". Our mail server requires you to authenticate to our servers by first connecting to the mail server to check mail before sending mail. This ensures you have a valid mail account on our servers and are not a spammer.
Sometimes, if you do not set your mail client to send/receive every 5 or 10 minutes while you're composing a message, the server "times out" and forgets who you are. When you try to send the message you were writing, it doesn't recognize you and rejects your message. So, if you set your mail client to send and receive mail every 5 or 10 minutes, this problem should be clear up.
Another cause could be that you do not have your mail client set to "This server requires authentication". Our mail server requires you to authenticate to our servers by first connecting to the mail server to check mail before sending mail. This ensures you have a valid mail account on our servers and are not a spammer.
Sometimes, if you do not set your mail client to send/receive every 5 or 10 minutes while you're composing a message, the server "times out" and forgets who you are. When you try to send the message you were writing, it doesn't recognize you and rejects your message. So, if you set your mail client to send and receive mail every 5 or 10 minutes, this problem should be clear up.
