diff --git a/examples/dotnet-03-simple-chatbot/MyAgentConfig.cs b/examples/dotnet-03-simple-chatbot/MyAgentConfig.cs
index 474fc9c8..fd905a87 100644
--- a/examples/dotnet-03-simple-chatbot/MyAgentConfig.cs
+++ b/examples/dotnet-03-simple-chatbot/MyAgentConfig.cs
@@ -58,7 +58,7 @@ public class MyAgentConfig : IAgentConfig
 
     [JsonPropertyName(nameof(this.ModelName))]
     [JsonPropertyOrder(80)]
-    public string ModelName { get; set; } = "GPT-4o";
+    public string ModelName { get; set; } = "gpt-4o";
 
     public void Update(object? config)
     {
diff --git a/examples/dotnet-03-simple-chatbot/appsettings.json b/examples/dotnet-03-simple-chatbot/appsettings.json
index 8cd56835..41b44757 100644
--- a/examples/dotnet-03-simple-chatbot/appsettings.json
+++ b/examples/dotnet-03-simple-chatbot/appsettings.json
@@ -29,7 +29,7 @@
     "Temperature": 0.0,
     "NucleusSampling": 1.0,
     "LLMProvider": "openai",
-    "ModelName": "GPT-4o"
+    "ModelName": "gpt-4o"
   },
   // Azure Content Safety settings
   "AzureContentSafety": {