log4net not logging https requests?

I just noticed that no https requests are logged by log4net on my Win 2008 server running ASP.NET 3.5. Http requests have been working fine for many months. Is there a simple fix for this? I'm not sure where to begin debugging. Configuration:

<log4net debug="false">
<appender name="file" type="log4net.Appender.RollingFileAppender">
    <file value="logs/Web.log"/>
    <threshold value="ALL"/>
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
    <appendToFile value="true"/>
    <rollingStyle value="Composite"/>
    <datePattern value="yyyy-MM-dd"/>
    <maxSizeRollBackups value="20"/>
    <maxi开发者_如何转开发mumFileSize value="10MB"/>
    <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date %-5level - %message%newline"/>
    </layout>
</appender>
<root>
    <level value="ALL"/>
    <appender-ref ref="file"/>
</root>
</log4net>