Log4j hit error but no mail sent?

[gan.gary]

I use a JBoss for queue. I have configured the SMTPAppender in "jboss-log4j.xml" in "C:\jboss-4.2.2.GA\server\default\conf". ( the add are hid)

<appender name="SMTP" class="org.apache.log4j.net.SMTPAppender">
 <errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
 <param name="Threshold" value="ERROR"/>
 <param name="To" value="[e-mail]"/>
 <param name="From" value="[e-mail]"/>
 <param name="Subject" value="JBoss Sever Errors"/>
 <param name="SMTPHost" value="ZZZ.com"/>
 <param name="BufferSize" value="10"/>
 <layout class="org.apache.log4j.PatternLayout">
 <param name="ConversionPattern" value="[%d{ABSOLUTE},%c{1}] %m%n"/>
 </layout>
 </appender>

The same settings I used for simple javaMail is working fine, but when I purposely let the JBoss hit error on my jar file, no mail sent. Any idea? where to check? And I also found the "org.jboss.mail.MailService" in jmx console cannot be configured anywhere, seems for free version.

[gan.gary]

if searching for "Log4j", it seems nothing can be found on

service=Logging,type=Log4jService

under "jboss.system"
&

J2EEApplication=null,J2EEServer=Local,ServiceModule=jboss-service.xml,j2eeType=MBean,name=jboss.system:type=Log4jService,service=Logging

under "jboss.management.local"

[gan.gary]

I forgot to add here as well:

<root>
 <appender-ref ref="CONSOLE"/>
 <appender-ref ref="FILE"/>
 <appender-ref ref="SMTP"/>
</root>