Problem

Confluence cannot reach the mail server, returns code 421 error which indicates that the service is not available and the connection will be closed.

The following appears in the atlassian-confluence.log:

2012-12-05 16:02:00,105 ERROR [scheduler_Worker-9] [atlassian.core.task.AbstractErrorQueuedTaskQueue] handleException com.atlassian.mail.MailException: javax.mail.MessagingException: Could not connect to SMTP host: 192.168.27.25, port: 2526, response: 421
com.atlassian.mail.MailException: javax.mail.MessagingException: Could not connect to SMTP host: 192.168.27.25, port: 2526, response: 421
at com.atlassian.mail.server.impl.SMTPMailServerImpl.send(SMTPMailServerImpl.java:191)
at com.atlassian.confluence.jmx.JmxSMTPMailServer.send(JmxSMTPMailServer.java:71)
at com.atlassian.confluence.mail.template.AbstractMailNotificationQueueItem.send(AbstractMailNotificationQueueItem.java:128)
at com.atlassian.confluence.mail.template.PreRenderedMailNotificationQueueItem.send(PreRenderedMailNotificationQueueItem.java:117)
at com.atlassian.confluence.mail.template.AbstractMailNotificationQueueItem.execute(AbstractMailNotificationQueueItem.java:99)
at com.atlassian.core.task.AbstractErrorQueuedTaskQueue$TaskDecorator.execute(AbstractErrorQueuedTaskQueue.java:107)
at com.atlassian.core.task.AbstractTaskQueue.flush(AbstractTaskQueue.java:45)
at com.atlassian.core.task.AbstractErrorQueuedTaskQueue.flush(AbstractErrorQueuedTaskQueue.java:37)
at com.atlassian.quartz.jobs.TaskQueueFlushJob.doExecute(TaskQueueFlushJob.java:32)
at com.atlassian.quartz.jobs.AbstractJob.executeInternal(AbstractJob.java:86)
at org.springframework.scheduling.quartz.QuartzJobBean.execute(QuartzJobBean.java:86)
at com.atlassian.confluence.setup.quartz.DelegatingClusterAwareQuartzJobBean.executeJob(DelegatingClusterAwareQuartzJobBean.java:16)

Diagnosis

1. Check that the SMTP is running on its host. If unsure, verify this with your System Administrator.
2. See if you can send mail with an application other than Confluence.
3. Check the physical connection from the Confluence box to the SMTP host with the following:
   

   Windows

   Expand to see Windows instructions

   Test that the server is reachable by pinging it.

   C:\>ping -n 1 smtp-host
   Pinging smtp-host.potatobake.com [192.168.1.100] with 32 bytes of data:
   Reply from 192.168.1.100: bytes=32 time=4ms TTL=127
   Ping statistics for 172.20.4.167:
       Packets: Sent = 1, Received = 1, Lost = 0 (0% loss),
   Approximate round trip times in milli-seconds:
       Minimum = 4ms, Maximum = 4ms, Average = 4ms
   
   

   Check that the port is open (typically 25). A successful connection to the port indicates it is open. If a successful connection is made, the screen will go blank. If not, the below message will be generated. To exit telnet, use CTRL+C.

   C:\>telnet smtp-host 25
   Connecting To smtp-host...Could not open connection to the host, on port 25: Connect failed

   Linux

   Expand to see Linux instructions

   Test that the server is reachable by pinging it.

   $ ping -c1 smtp-host
   PING smtp-host (192.168.1.100): 56 data bytes
   64 bytes from 192.168.1.100: icmp_seq=0 ttl=127 time=0.521 ms
    
   --- crowd-ad1 ping statistics ---
   1 packets transmitted, 1 packets received, 0.0% packet loss
   round-trip min/avg/max/stddev = 0.521/0.521/0.521/0.000 ms

   Check that the port is open (typically 25). A successful connection to the port indicates it is open. To exit telnet, use CTRL+C.

   $ telnet smtp-host 25
   Trying 192.168.1.100...
   Connected to smtp-host.
   Escape character is '^]'.

4. If you're unable to connect to the SMTP host from the JIRA host, it may indicate a problem with the network. Please check this with your hosting provider or System Administrator.

Cause

The Mail Sever is not available/reachable.

 Resolution 1

 Re-create the SMTP server settings in Confluence Admin > Mail Server. 

Resolution 2

 If the above does not work, move the 'activation' and 'mail' jar files from /confluence/WEB-INF/lib to <Confluence Standalone install>/lib, restart Confluence and see if the problem persists.