If your are using Microsoft Outlook or Thunderbird you need to change the SMTP settings when using our email servers for SMTP - many people don't use our servers and just use their local ISP. Please make these changes if you are having any email sending problems. Squirrelmail and Webmail users are not affected by this.
Many ISPs are now blocking port 25 outbound from end users to prevent spam from their network. A new standard is to use port 587 and setup expiry.com's email servers to listen on port 587.
To setup Outlook Express - do this
1) Open Outlook.
2) Tools -> Accounts
3) go to the "Mail" tab.
4) select the account and click "Properties".
5) Change the "Outgoing Mail Server" to "mail.yourdomainname.com"
6) Go to the "Outgoing Server" Tab in the new window.
7) Checkmark the "Outgoing Server (SMTP) requires authentication" option and select the "Use same settings as my incoming server" option. Hit "Ok".
8) Go to the "Advanced" Tab in the new window.
9) Set the "Outgoing mail (SMTP)" option to 587 from 25. Hit "Ok".
To setup Outlook 2003 - do this
1) Open Outlook.
2) Tools -> Accounts
3)Select Email/View or change existing accounts.
4) select the account and click "Change".
5) Change the "Outgoing Mail Server" to "mail.yourdomainname.com".
6) Select the "Outgoing Server" tab
7) Checkmark the "Outgoing Server (SMTP) requires authentication" option and select the "Use same settings as my incoming server" option. Hit "Ok".
8) Go to the "Advanced" Tab in the new window.
9) Set the "Outgoing Server (SMTP)" option to 587 from 25. Hit "Ok".
To setup Outlook 2007 - do this
1) Open Outlook.
2) Tools -> Accounts
3) Select Email
4) select the account and click "Change".
5) Change the "Outgoing Mail Server" to "mail.yourdomainname.com".
6) Select "More Settings"
7) Select the "Outgoing Server" tab
8) Checkmark the "MY Outgoing Server (SMTP) requires authentication" option and select the "Use same settings as my incoming server" option.
9) Go to the "Advanced" Tab in the same window.
10) Set the "Outgoing Server (SMTP)" option to 587 from 25. Hit "Ok".
11) Click on "Next", "Finish"
Outlook should now use port 587 for sending mail if the settings look like the screen shots shown below. 
Please ensure that the SMTP port number is set to 587 and that the option "My outgoing server(SMTP) requires authentication" is selected.
Below are instructions on how to configure SMTP authentication across various EMAIL Clients.
Microsoft Outlook Express and Outlook 2000
1.) Click Tools
2.) Click Accounts
3.) Click the Mail tab
4.) Double-click on the email account
5.) Verify that the email address is entered in all lowercase letters (General Tab)
6.) Click the Servers tab.
7.) Verify that "Server Requires Authentication" is checked
8.) Click the Settings button and verify that "Login using same settings as my incoming mail server" is selected
9.) Click 'Apply' (if available), then 'OK', and then 'Close'.
Microsoft Outlook 2002 (XP) and 2003
1.) Click Tools
2.) Click Email Accounts
3.) Click View or Change Existing Email Accounts
4.) Click Next
5.) Double-click on the email account
6.) Click on More Settings and then click the Outgoing Server tab.
7.) Verify that "SMTP server requires authentication" is checked and "Use same settings as my incoming mail server is selected"
8.) Click 'OK', then 'Next', and then 'Finish'
9.) Click send / receive to check for errors
Mozilla Thunderbird
1.) Click Tools
2.) Click Account Settings
3.) Click Outgoing Server from the left
4.) Select the email outgoing server
5.) Click the Edit button
6.) Verify that Use Name and Password is checked
7.) Verify the username is entered correctly
Apple Mail
1.) Click Mail
2.) Click Preferences
3.) Click the email account
4.) Click the Account Information button
5.) Click the Server Settings button
6.) Verify that Authentication is set to Password
7.) Verify that username and password are entered correctly
Microsoft Entourage
1.) Click Tools
2.) Click Accounts
3.) Click Mail
4.) Double-click on the email account
5.) Click Account Settings
6.) Click the Advanced Sending Options button
7.) Verify that Override SMTP Port to 587 and that "SMTP server requires authentication" is checked and "Use same settings as receiving mail server" is selected
8.) Close the window by clicking the box in upper-left corner
Qualcomm Eudora
1.) Click the Eudora menu
2.) Click Preferences
3.) Click the Checking Mail icon
4.) Verify that 'Authentication' is set to Passwords
5.) Click the Sending Mail icon
6.) Verify that Allow Authorization is checked
