Microsoft KB Archive/279985

= SBS POP3 Connector Does Not Report Actual POP3 Server Errors =

Article ID: 279985

Article Last Modified on 1/25/2006

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APPLIES TO


 * Microsoft Small Business Server 2000 Standard Edition
 * Microsoft BackOffice Small Business Server 4.5

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This article was previously published under Q279985



SYMPTOMS
When you are attempting to access a Post Office Protocol 3 (POP3) server with the POP3 Connector for Small Business Server (SBS), the POP3 Connector may be unable to connect and download email from the POP3 server and may log the following events:

Event ID: 12050

Source: POP3 Connector

Type: Error

Category: Download

Description: Failed to check the POP3 account for  at host   on port 110. The error is 86.

Event ID: 12052

Source: POP3 Connector

Type: Error

Category: Download

Description: An error occurred during a POP3 transaction to host [ ]. For user. The error is 86.

Event ID: 4017

Source: POP3 Connector

Type: Information

Category: Download Description: We have been denied access to [ ] logging as. Verify the password for the account.

The error code 86 corresponds to the &quot;Incorrect Password&quot; or &quot;Access Denied&quot; error messages. These errors may be logged even though the POP3 account and password information for the POP3 mailbox is correct.



CAUSE
These events may be logged for any type unsuccessful authentication, including incorrect password, incorrect username, incorrect password and username combination, or if another session is locking the mailbox. This error may also be logged if you disable the POP3 account.



MORE INFORMATION
When the POP3 Connector establishes a session with a POP3 server, it sends the POP3 protocol user command followed by the account name. If the user does not exist, the POP3 server may reply with the -ERR response to the user command. For security reasons, the POP3 server generally sends the +OK response after a user command. If the POP3 Connector receives a +OK response, it sends a pass command together with the password. A successful logon attempt is followed by a +OK response from the POP3 server. If the logon attempt is not successful, the POP3 Connector receives the -ERR response.

The response from a POP3 server to the user and pass commands is only significant to the +OK and -ERR responses. If the POP3 Connector receives a -ERR response, it is unable to determine the reason for the unsucessful authentication and thus reports the errors that you find in the &quot;Symptoms&quot; section in this article.

Some POP3 servers may provide a description string after the -ERR response, for example:

-ERR Incorrect username and/or password.

Anything after +OK or -ERR is specific to the POP3 sever implementation. It is possible to enable the POP3 Connector diagnostic logging to check for a descriptive message after the -ERR response. You may also use Telnet and the POP3 protocol commands to check for the response. For additional information about using Telnet to troubleshoot access to a POP3 mailbox, click the article number below to view the article in the Microsoft Knowledge Base:

196748 How to Use Telnet to Test an Internet Mail Connection

Diagnostic Logging: SBS 4.5
To enable diagnostic logging for the POP3 Connector on SBS 4.5, follow these steps:
 * 1) Click Start, point to Programs, point to Microsoft Exchange, and then click Microsoft Exchange Administrator.
 * 2) In the left pane, expand the   container, which by default in SBS should be the server name.
 * 3) Expand the   container.
 * 4) Under the   container, click the   container.
 * 5) In the right pane, double-click Connector for POP3 Mailboxes to view the properties.
 * 6) On the Diagnostic Logging tab, verify that the Enable event logging on the services check box is selected.
 * 7) Under Category, click Delivery Services.
 * 8) Set SMTP Client Transactions and POP3 Client Transactions to Maximum.
 * 9) Click OK, and then click Yes to restart the POP3 Connector Service.

Diagnostic Logging: SBS 2000
To enable diagnostic logging for the POP3 Connector on SBS 2000, follow these steps:
 * 1) Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager.
 * 2) In the left pane, expand the Connectors node.
 * 3) Right-click Connector for POP3 Mailboxes, and then click Properties.
 * 4) In the Connector for POP3 Mailboxes Properties dialog box, click Diagnostic Logging.
 * 5) Verify that the Enable event logging on the services check box is selected.
 * 6) Under the Services box, click Delivery Service, and under Logging Level click Maximum.
 * 7) Click OK to apply changes.
 * 8) Close the System Manager console.
 * 9) Click Start, point to Programs, point to Administrative Tools, and then click Services.
 * 10) In the left pane, right-click Microsoft Connector for POP3, and then click Restart. After the service restarts, close the Services Management console.

When the POP3 Connector attempts to download messages from the POP3 server it will log a number of events in the Application Log of Event Viewer. You need to wait until the next scheduled download attempt or you can also initiate the download by using the Deliver Now option in the POP3 Connector Properties dialog box. You can then use Event Viewer and search for Event ID 4023, and Source: POP3Connector in the Application Log.

The event 4023 contains the POP3 Protocol transcript between the POP3 server and the POP3 Connector. There should be at least one event 4023 for each individual POP3 mailbox and Global POP3 accounts configured in the POP3 Connector. You will have to view the description of each one until you find the entry that corresponds to the mailbox that is failing.

If you double click on the entry for an event 4023, the description contains the POP3 transcript. You should be able to identify the corresponding account by looking at the entry following the user command. This should be the username for the POP3 account that the POP3 Connector is attempting to access. You should also be able to see the -ERR response after the user command or the pass command. Check if there are any descriptive messages after the -ERR command such as &quot;Access Denied&quot; or &quot;Unable to Lock Mailbox.&quot; The transcript should be similar to this sample:   C: USER username S: +OK Password required for user username C: PASS secret S: -ERR maildrop already locked ... If the mailbox is locked by another session, you need to end that session before accessing the mailbox. Also, verify with your Internet service provider that your username and password are correct and that the POP3 account is enabled.

You should disable diagnostic logging for the POP3 Connector after you have finished troubleshooting. Follow the appropriate method for diagnostic logging earlier in this article and set the logging level back to minimum.

For additional information about Event ID 12050, click the article number below to view the article in the Microsoft Knowledge Base:

243587 POP3 Gateway Connector Cannot Download Mail from POP3 Server

Additional query words: smallbiz SBS

Keywords: kberrmsg kbprb KB279985

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