Hi sasi,
Please open the log4j to debug level for "net.jforum":
<category name="net.jforum">
<priority value="debug" />
<appender-ref ref="jforum.log" />
</category>
And check to see jforum.log has the output like:
2012-06-14 18:04:22,494 DEBUG [POPListener] - Going to check [email=myforum@andowson.com, host=pop.gmail.com, port=995, ssl=true]
2012-06-14 18:04:24,647 DEBUG [POPParser] - Retrieved message [subject=xxx, sender=somebody@gmail.com, replyTo=somebody@gmail.com, references=null, inReplyTo=null, contentType=multipart/alternative; boundary=bcaec55239806595f304c26bd2c0, date=Thu Jun 14 18:04:13 CST 2012, content=xxx
, headers={Return-Path=<somebody@gmail.com>, MIME-Version=1.0, Message-ID=<CAOECkF9FRpsDo0QzN3Y2X59DgRCe0=7WduXxha3664z_QfBTrw@mail.gmail.com>, Subject=xxx, To=myforum@andowson.com, Authentication-Results=mx.google.com; spf=pass (google.com: domain of somebody@gmail.com designates 209.85.215.54 as permitted sender) smtp.mail=somebody@gmail.com; dkim=pass header.i=@gmail.com, Delivered-To=myforum@andowson.com, Received-SPF=pass (google.com: domain of somebody@gmail.com designates 209.85.215.54 as permitted sender) client-ip=209.85.215.54;, Date=Thu, 14 Jun 2012 18:04:13 +0800, DKIM-Signature=v=1; a=rsa-sha256; c=relaxed/relaxed;
d=gmail.com; s=20120113;
h=mime-version:date:message-id:subject:from:to:content-type;
bh=zkMh7UVpYi+PiiEMS1BWEQEsV/UNFyhuT0SAVWBOrrg=;
b=i0g03JvdUxUNgnBSwHye/j1dggRB4+aYd7cXPtYWB1ZenUhUM90u8zPOkvdwggIh2C
u2ecRk3zWfDmgQAvt7uhhL10hFpvEfjjX+dHenEZ/LWAH8hCEbC/ETEClMsItpRkz5Rw
zgvJpz6xpNkmPjpC3a7ZTl4cwE+KuNIF7gKQ06ys6op7bbQ0Em/Xij/qkGKeAooX5A2O
rfL0PJW4P6dCMaY7ZSHIjNbqIa3jB5uYTW2p4nmcQlLgURxITZFmHpS8b2lPhgXU7x7b
zwYmiBkuGt9x4ESkhGCWGU9qYJdB4jVS7jdNah6TRxRMJiymALO1khBGZ5UpTEmQG07m
Emyw==, Received=by 10.112.84.233 with HTTP; Thu, 14 Jun 2012 03:04:13 -0700 (PDT), Content-Type=multipart/alternative; boundary=bcaec55239806595f304c26bd2c0, From=Andowson Chang <somebody@gmail.com>}]