diff --git a/DysonNetwork.Pass/Auth/AuthController.cs b/DysonNetwork.Pass/Auth/AuthController.cs
index 0cf2894..4bd7be4 100644
--- a/DysonNetwork.Pass/Auth/AuthController.cs
+++ b/DysonNetwork.Pass/Auth/AuthController.cs
@@ -20,12 +20,12 @@ public class AuthController(
 ) : ControllerBase
 {
     private readonly string _cookieDomain = configuration["AuthToken:CookieDomain"]!;
-    
+
     public class ChallengeRequest
     {
         [Required] public ClientPlatform Platform { get; set; }
-        [Required] [MaxLength(256)] public string Account { get; set; } = null!;
-        [Required] [MaxLength(512)] public string DeviceId { get; set; } = null!;
+        [Required][MaxLength(256)] public string Account { get; set; } = null!;
+        [Required][MaxLength(512)] public string DeviceId { get; set; } = null!;
         [MaxLength(1024)] public string? DeviceName { get; set; }
         public List<string> Audiences { get; set; } = new();
         public List<string> Scopes { get; set; } = new();
@@ -48,6 +48,8 @@ public class AuthController(
         var ipAddress = HttpContext.Connection.RemoteIpAddress?.ToString();
         var userAgent = HttpContext.Request.Headers.UserAgent.ToString();
 
+        request.DeviceName ??= userAgent;
+
         // Trying to pick up challenges from the same IP address and user agent
         var existingChallenge = await db.AuthChallenges
             .Where(e => e.AccountId == account.Id)
@@ -295,4 +297,4 @@ public class AuthController(
         });
         return Ok();
     }
-}
\ No newline at end of file
+}