XFOR: POP3 or IMAP4 Client Cannot Send SMTP Mail (200788)

SUMMARY

If you use incorrect logon credentials on a Post Office Protocol version 3 (POP3) or Internet Message Access Protocol, Version 4rev1 (IMAP4) client (when connecting to a Microsoft Exchange Server Internet Mail Service or Exchange 2000 Server SMTP connector to send outgoing SMTP mail) that is configured to enter authentication credentials for the outgoing mail server, you may receive one of the following error messages:

If the client is connected to an Exchange Server computer, the following event may be logged in the Exchange Server computer's application event log:
Event ID: 4183
Source: MSExchange IMC
Type: Error
Category: SMTP Interface Events

Authentication attempt (AUTH LOGIN) from hostname as ntdomain\userid failed: LogonUser() call failed with error: Logon failure: unknown user name or bad password.
If the client is connected to an Exchange 2000 server, you may receive the following SMTP error message:
505 5.7.3 Client was not authenticated

MORE INFORMATION

When you enter the logon credentials at the client, use the correct user name and password, or configure the client so that the outgoing mail server does not require authentication. See the section below.

If the Exchange Server computer's Internet Mail Service or the Exchange 2000 server SMTP connector is not configured to require authentication from the hosts (or clients) that connect to it, then the client does not need to be configured to require authentication.

To determine if the server requires authentication:

If the client connects to an Exchange Server Internet Mail Service:
1. In the Exchange Server Administrator program, open the properties for the Internet Mail Service object.
2. Click the Connections tab.
3. Under Accept Connections, if From any host (secure or non-secure) is selected, the client does not need to be configured to require authentication on the outgoing mail server.
4. Under Accept Connections, if Only from hosts using Authentication is selected, the client does need to be configured to require authentication on the outgoing mail server.
If the client connects to an Exchange 2000 server SMTP connector:
1. Start System Manager; click Start, point to Programs, point to Microsoft Exchange, and then click System Manager.
2. Locate the virtual server.
3. Right-click the virtual server, and then click Properties.
4. Click the Access tab, and then click Authentication under Access control.
5. In the Authentication Methods dialog box, if Anonymous Access is selected, the client does not need to be configured to require authentication on the outgoing mail server.
6. In the Authentication Methods dialog box, if Basic authentication or Integrated Windows authentication is selected, the client does need to be configured to require authentication on the outgoing mail server.

To determine if a Microsoft Outlook Express client is configured to require authentication when connecting to an outgoing mail server, perform the following steps. For other clients, refer to that client's documentation.

In Outlook Express, on the Tools menu, click Accounts.
Select the mail account, and then click Properties.
Click the Servers tab, and find the Outgoing Mail Server area.
If the Exchange Server Internet Mail Service requires authentication, click to select the My server requires authentication check box, and then click Settings to enter the logon information.
If the Exchange Server Internet Mail Service does not require authentication, do not select My server requires authentication.