Asking about log4net just write to appender when i stopped site

Question

Currently, I already config my project, but I got the issue

1. I can't query any message when the site is running.
2. When I stop the site, I can query it on database again and I see them.

Why do I just see message when I stop the site?
This is my code.

<log4net>
  <root>
    <level value="ALL" />    
    <appender-ref ref="asyncForwarder" />
  </root>
  <appender name="AdoNetAppender" type="log4net.Appender.AdoNetAppender">   
    <bufferSize value="4096" />
    <connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />    
    <connectionString value="data source=***;initial catalog=***;integrated security=false;persist security info=True;User ID=***;Password=***" /> 
    <commandText value="INSERT INTO LogAPI ([Date],[Thread],[Level],[Logger],[Message],[Exception]) VALUES (@log_date, @thread, @log_level, @logger, @message, @exception)" />
    <parameter>
      <parameterName value="@log_date" />
      <dbType value="DateTime" />
      <layout type="log4net.Layout.RawTimeStampLayout" />
    </parameter>
    <parameter>
      <parameterName value="@thread" />
      <dbType value="String" />
      <size value="255" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%thread" />
      </layout>
    </parameter>
    <parameter>
      <parameterName value="@log_level" />
      <dbType value="String" />
      <size value="50" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%level" />
      </layout>
    </parameter>
    <parameter>
      <parameterName value="@logger" />
      <dbType value="String" />
      <size value="255" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%logger" />
      </layout>
    </parameter>
    <parameter>
      <parameterName value="@message" />
      <dbType value="String" />
      <size value="4000" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%message" />
      </layout>
    </parameter>
    <parameter>
      <parameterName value="@exception" />
      <dbType value="String" />
      <size value="2000" />
      <layout type="log4net.Layout.ExceptionLayout" />
    </parameter>
  </appender>
  <appender name="asyncForwarder" type="Log4Net.Async.ParallelForwardingAppender,Log4Net.Async">
    <appender-ref ref="AdoNetAppender" />
    <bufferSize value="4096" />
  </appender>
</log4net>

I dont know what is correct concept on the log4net.