diff --git a/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/src/AuthenticationEventResponseHandler.cs b/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/src/AuthenticationEventResponseHandler.cs
index fd810afb63c13..664f34b5274d9 100644
--- a/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/src/AuthenticationEventResponseHandler.cs
+++ b/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/src/AuthenticationEventResponseHandler.cs
@@ -57,7 +57,7 @@ public Task SetValueAsync(object result, CancellationToken cancellationToken)
             {
                 if (result == null)
                 {
-                    throw new ValidationException(AuthenticationEventResource.Ex_Invalid_Return);
+                    throw new ArgumentNullException("AuthenticationEventResponseHandler", AuthenticationEventResource.Ex_Invalid_Return);
                 }
 
                 if (result is AuthenticationEventResponse action)
diff --git a/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/tests/Payloads/TokenIssuanceStart/NullResponse.json b/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/tests/Payloads/TokenIssuanceStart/NullResponse.json
index bfa3fc136c4a6..20d91a5f4b7cf 100644
--- a/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/tests/Payloads/TokenIssuanceStart/NullResponse.json
+++ b/sdk/entra/Microsoft.Azure.WebJobs.Extensions.AuthenticationEvents/tests/Payloads/TokenIssuanceStart/NullResponse.json
@@ -1,3 +1,3 @@
 {
-  "errors": [ "Return type is invalid, please return either an AuthEventResponse, HttpResponse, HttpResponseMessage or string in your function return." ]
+  "errors": [ "Return type is invalid, please return either an AuthEventResponse, HttpResponse, HttpResponseMessage or string in your function return. (Parameter 'AuthenticationEventResponseHandler')" ]
 }