public Startup(IHostingEnvironment env, ILoggerFactory loggerFactory) { //Configuration = SetupConfigurationBuilder(configurationBuilder, env); it looks like the default provider does not have a IConfiguartionBuilder registered on app init Configuration = SetupConfigurationBuilder(new ConfigurationBuilder(), env); _logger = loggerFactory.AddCreateCustomLogger(Configuration, env); _logger.LogInformation("Created and added custom logger"); }