I can't send mail! And the error says: 553 sorry, that domain isn't in my list of allowed rcpthosts.

This is the cryptic way our servers say "Relaying denied." Or, more specifically "You are coming from an untrusted place on the Internet and we aren't going to allow you to send mail through our servers."

How to make this go away.

You'll need to change two settings:

• SMTP authentication needs to be turned "on"
• Your Outgoing server (SMTP) port needs to be changed from 25 to 587.

Here's how to do it in Outlook:

1. Click Tools -> Accounts -> View or change existing e-mail accounts -> Next -> Select your account -> Change.
2. Click -> "More Settings"
3. Click the "Outgoing Server" tab.
4. Check the box next to "My outgoing server (SMTP) requires authentication."
5. Make sure "Use same settings as my incoming mail server" is selected.
6. Select the "Advanced" Tab.
7. Change the "Outgoing server (SMTP):" port from 25 to 587.
8. Done!

Here's how to do it in Mac Mail :

1. Open Mail. In the menu bar, choose Mail -> Preferences, and then click Accounts.
2. From the Accounts list, select your account, and then click the Account Information tab.
3. Click on the the Outgoing Mail Server (SMTP) drop down, then on the pop-up menu, choose Edit SMTP Server List.
4. From the list of servers, select your server and then click the Advanced tab.
5. Uncheck the Automatically dectect and maintain account settings button.
6. Change the "Server port" to 587.
7. Use SSL should be checked.
8. Authentication should be MD5 Challenge-Response
9. Allow insecure authentication should be unchecked.
10. Enter your full email address in the User Name: field
11. Enter your email password in the Password: field.
12. Click OK.
13. Close the Account Settings window.
14. Done!

These settings will allow you to send mail through our servers from anywhere, at anytime.