Few things to check here, what version of the logentries.log4net
nuget did you install? You can check this if you're using VS in your Nuget package manager. (Note that there's only v2.4.0) But there is an old library upto v2.3.9 called le_log4net which is deprecated, I have to change the title on the package. Secondly, if you paste the content of your web/app.config, only important parts are the log4net block and you appSettings. Lastly, be sure to place the following in your AssemblyInfo.cs
as its sometimes overlooked.
[assembly: log4net.Config.XmlConfigurator(ConfigFile="Web.config", Watch = true)]
You can email me at mark@logentries.com or use our in-app support (I'm with Logentries and wrote the .NET libs.) as it may be quicker than debugging on here. Although its no harm doing it here so as to keep the solution public.