diff --git a/src/Serilog.Settings.AppSettings/AppSettingsLoggerConfigurationExtensions.cs b/src/Serilog.Settings.AppSettings/AppSettingsLoggerConfigurationExtensions.cs
index c1d3e2b..cf4b2b1 100644
--- a/src/Serilog.Settings.AppSettings/AppSettingsLoggerConfigurationExtensions.cs
+++ b/src/Serilog.Settings.AppSettings/AppSettingsLoggerConfigurationExtensions.cs
@@ -39,7 +39,7 @@ public static class AppSettingsLoggerConfigurationExtensions
         /// <returns>An object allowing configuration to continue.</returns>
         [EditorBrowsable(EditorBrowsableState.Never)]
         public static LoggerConfiguration AppSettings(
-            this LoggerSettingsConfiguration settingConfiguration, string settingPrefix = null)
+            this LoggerSettingsConfiguration settingConfiguration, string settingPrefix)
         {
             return AppSettings(settingConfiguration, settingPrefix, filePath: null);
         }