How to set LogLevel to error in log4net for hangfire

Add this logger to your web.config (log4net section)

<logger additivity="false" name="Hangfire">
   <level value="ERROR" />
   <appender-ref ref="HangfireLoggerAppender" />
</logger>

Adding to what @Martino mentioned above here is the exact location to add that tag in log4net section:

<log4net debug="true">
  <root>
    <level value="ALL" />
    <appender-ref ref="LogFileAppender" />
  </root>
  <appender name="LogFileAppender" type="log4net.Appender.FileAppender">
    <file type="log4net.Util.PatternString" value="%property{LogFileName}" />
    <appendToFile value="true" />
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date %level %logger - %message%newline" />
    </layout>
  </appender>
  <logger additivity="false" name="Hangfire">
    <level value="ERROR" />
    <appender-ref ref="HangfireLoggerAppender" />
  </logger>
</log4net>