Mail problems

Generally, common problems dealing with individual mail messages are handled by creating an undeliverable mail notification when the mail message becomes undeliverable.

  • If ReturnToMailFrom is set to YES on the UNDELIVERABLE statement or the default value is used, an undeliverable mail notification is created that contains the original mail text as well as additional information that indicates the reason why the mail could not be delivered. The undeliverable mail notification is sent to the originator's mail address as specified on the MAIL FROM command.
  • If requested, a report is generated that contains the error text indicating why the mail message could not be delivered. The report is handled according to the setting on the REPORT configuration statement. See z/OS Communications Server: IP Configuration Reference for details.
The following steps help in debugging mail problems.
  1. Start by reviewing the error text captured in the undeliverable mail notification for the undeliverable mail message. The following list contains reasons why mail can become undeliverable.
    • Common problems with mail messages can be that there are no target servers with the correct capabilities to send the mail, such as the following:
      • The mail requires a TLS connection. This requires the target server to be an ESMTP which supports the EHLO SMTP command and the extension option STARTTLS. The target server must reply positively to the STARTTLS command (2xx reply code). Also the CSSMTP application must be able to successfully issue the socket ioctl() to communicate with the TCP/IP stack to establish the TLS connection.
      • The mail message size is larger than what the target server indicates it can support on the EHLO reply response when it is an ESMTP server.
      • The mail message size is larger than what is configured on the parameter MessageSize associated with the TargerServer statement when it is an SMTP server.
    • Target server replies to SMTP commands with a 4xx reply code, which indicates that the mail message send be retried. However, the number of retries exceeded the configured maximum, see the statement RetryLimit in z/OS Communications Server: IP Configuration Reference for more information.
    • Target server connection timeouts occur, which indicates that the mail message send be retried. However, the number of retries exceeded the configured maximum, see the statement RetryLimit in z/OS Communications Server: IP Configuration Reference for more information.
    • Target server replies to MAIL FROM, RCPT TO, DATA and sending end of mail (EOM) sequence with a 5xx reply code indicating failure.
    The following example shows general error text for a single recipient in the undeliverable mail notification.
    Figure 1. Example of undeliverable mail notification
     [1]  Received: from host1.ibm.com (host1)
  by host2.ibm.com (host2 [x.x.x.x])
  for <USER1@host1>
  with ESMTP (IBM CSSMTP z/OS V01R11.00)
  Id SMTP2.JOB00051.host2@ibm.com.Nov192008.134147.442406.1U ;
 Wed, 19 Nov 2008 13:54:31 -0500
 [2]  Date: Wed, 19 Nov 2008 13:54:31 -0500
 [3]  From: <CSSMTP@host2.ibm.com>
 [4]  To: <user1@ibm.com>
 [5]  Subject: Undeliverable Mail for MSG-ID SMTP2.JOB00051.host2@ibm.com.Nov192008.134147.442406.1

 [6]  Error text: No target server capable of receiving mail:   
retry limit count exceeded for this mail. Tried (1).    

 [7]  Mail was not delivered to the following recipients:
 [8]    <user2@samehost.ibm.com>    
 [9]    <user3@samehost.ibm.com>    
 [10]   Reply text:550 Recipient unknown 
 [11]   <user4@samehost.ibm.com>    
 [12]   <user5@badhost.ibm.com>                 
 [13]   Reply text:550 "badhost" not found 

  

 [14]  Original mail text:
   Received: from host1.ibm.com (host1)
     by host2.ibm.com (host2 [x.x.x.x])
     for <USER1@host1>
     with ESMTP (IBM CSSMTP z/OS V01R11.00)
     Id SMTP2.JOB00051.host2.ibm.com.Nov192008.134147.442406.1 ;
    Wed, 19 Nov 2008 13:53:18 -0500
   FROM:     user1@ibm.com
   TO:       user2@samehost.ibm.com, user3@samehost.ibm.com, user4@samehost.ibm.com, user5@badhost.ibm.com
   SUBJECT: MSG1 JOB SMTP2 EHLO
   Date: Wed, 19 Nov 2008 13:53:18 -0500
   Message-ID: <SMTP2.JOB00051.host2@ibm.com.Nov192008.134147.442406.1>

   This is only a test.
     [1] 
    Receive line for the undeliverable mail notification.
     [2] 
    Date and time the undeliverable mail notification was created.
     [3] 
    The email address of the CSSMTP application that created the undeliverable mail notification.
     [4] 
    The email address to whom the undeliverable mail notification is sent.
     [5] 
    The subject line showing the MSG-ID SMTP2.JOB00051.host2@ibm.com.Nov192008.134147.442406.1 for the original piece of mail. This is the same value as the Message-ID header in the original mail text.
     [6] 
    General error text applies to all recipients that mail was not delivered to that do not have a specific error reply text. In this example, the general error text applies to the recipients in line [8] and [11].
     [7] 
    After this line, the list of recipients that did NOT receive the original mail text.
     [9] 
    Original mail text was not delivered to this recipient <user3@samehost.ibm.com> because of the specific error described in line [10] reply text. This recipient was unknown to the target server.
     [12] 
    Original mail text was not delivered to this recipient <user5@badhost.ibm.com> because of the specific error described in line [13] reply text. The email address of the recipient was not acceptable to the target server.
     [14] 
    The original mail message - headers and content.
Table 1. Common mail text problems
Symptoms Problem/Cause Action
No target server capable of receiving mail: original message size too large. The mail size is too large. Check size of the mail including headers.

Use the MODIFY DISPLAY TARGETS command, see z/OS Communications Server: IP System Administrator's Commands to know what mail size is supported by target servers and whether the target server is SMTP or ESMTP.

 If appropriate reduce mail size and resend.

Otherwise, increase the mail size supported by the target server. To check target server configuration, see TargetServer statement in z/OS Communications Server: IP Configuration Reference if SMTP. Correct the target server on remote host if it is ESMTP.
No target server capable of receiving mail: retry count or interval is zero for this mail. Review the log file. The target server is using reply code 4xx or is timing out the connection which requires a retry to occur. Correct the target server or add a new target to the configuration. Change statement RetryLimit to allow retries to occur.
No target server capable of receiving mail: retry limit count exceeded for this mail. Review the log file. The target server is using reply code 4xx or is timing out the connection which requires a retry to occur. Correct the target server or add a new target to the configuration.
No target server capable of receiving mail: TLS support not available. The batch job containing this mail required a TLS connection. The STARTTLS command is part of the batch job.

Use the MODIFY DISPLAY TARGETS command. See z/OS Communications Server: IP System Administrator's Commands to determine whether TLS is supported by the target servers. Target servers must be ESMTP to support TLS.

 If appropriate remove STARTTLS command from batch job.

Check the target server configuration. Review the log file for the reply code from the target server or connection timeout which requires a retry to occur. Correct the target server or add a new target server capable of doing TLS to configuration.
Table 2. Dead letters problems
Symptoms Problem/Cause Action
EZD1826I This message indicates that the dead letters cannot be written to the configured or default dead letter directory. For details and other messages, see the appropriate EZD1826I message in z/OS Communications Server: IP Messages Volume 2 (EZB, EZD).

No more dead letters are stored. The CSSMTP application internally sets the DeadLetterAction statement as it was set to Delete. The user can automate on this message to monitor storage utilization, and decide whether MODIFY SUSPEND command should be issued to suspend all new spool file processing and should examine and clean up all stored and unneeded dead letters to free up storage. Then MODIFY REFRESH command should be issued with DeadLetterAction set to STORE to tell the CSSMTP application to write dead letters into the configured or default dead letter directory again. MODIFY RESUME command is issued (if MODIFY SUSPEND command was issued previously) to resume new spool file processing.

Table 3. Mail Directory problems
Symptoms Problem/Cause Action
EZD1827I This message indicates that mail messages cannot be written to the configured or default mail directory associated with the ExtendedRetry statement.

For details and other messages, see the appropriate EZD1827I message in z/OS Communications Server: IP Messages Volume 2 (EZB, EZD).

No more extended retry mail messages are stored. The CSSMTP application ends.

Look up the return code and reason code values associated with the console message to determine the next action to take.

If you determine that the z/OS® UNIX file system mail directory is not accessible in write mode, perform one of the following actions:
  • Mount the z/OS UNIX file system in write mode.
  • Specify a new directory on the MailDirectory parameter of the ExtendedRetry configuration statement in the CSSMTP configuration file. CSSMTP must have write access to this directory.

Restart the CSSMTP application.
EZD1852I This message indicates that mail messages cannot be stored to the configured or default mail directory associated with the ExtendedRetry statement because the file system is out of space.

For details and other messages, see the appropriate EZD1852I message in z/OS Communications Server: IP Messages Volume 2 (EZB, EZD).

No more extended retry mail messages are stored. The CSSMTP application ends.

Perform one of the following actions and restart the CSSMTP application:
  • Delete any files in the file system that are no longer needed.
  • Define a new mail directory on z/OS UNIX file system with more space:
    1. Define a new larger file system.
    2. Mount the file system.
    3. Use the mkdir command to define a new mail directory.
    4. Copy all the files from the old mail directory to the new mail directory.
    5. Update the configuration to use the new mail directory.