diff --git a/CometServer/Modules/Authentication/UsernameModule.cs b/CometServer/Modules/Authentication/UsernameModule.cs
index 53637718..c501f688 100644
--- a/CometServer/Modules/Authentication/UsernameModule.cs
+++ b/CometServer/Modules/Authentication/UsernameModule.cs
@@ -134,7 +134,7 @@ public override void AddRoutes(IEndpointRouteBuilder app)
                 try
                 {
                     identity = await this.Authorize(appConfigService, credentialsService, req);
-                    await res.WriteAsync(credentialsService.Credentials.UserName);
+                    await res.AsJson(credentialsService.Credentials.UserName);
                 }
                 catch (AuthorizationException)
                 {