So while building this Umbraco site I wanted to use a custom log4net appender, in this case I wanted to connect log4net to logentries to be able to track my logs online. Normally when wanting to use log4net and send to logentries u just install a Nuget package and setup the appender in the log4net.config. But since log4net comes bundled in Umbraco in a none nuget-package kind of way, when installing the appender package my site crashed.