change authentication flow

Emby.Server.Implementations/Session/SessionManager.cs

@@ -1379,21 +1379,17 @@ namespace Emby.Server.Implementations.Session
                 user = _userManager.GetUserByName(request.Username);
             }
 
-            if (user != null)
+            if (user == null)
             {
-                // TODO: Move this to userManager?
+                AuthenticationFailed?.Invoke(this, new GenericEventArgs<AuthenticationRequest>(request));
+                throw new SecurityException("Invalid username or password entered.");
+            }
+
             if (!string.IsNullOrEmpty(request.DeviceId)
                 && !_deviceManager.CanAccessDevice(user, request.DeviceId))
             {
                 throw new SecurityException("User is not allowed access from this device.");
             }
-            }
-
-            if (user == null)
-            {
-                AuthenticationFailed?.Invoke(this, new GenericEventArgs<AuthenticationRequest>(request));
-                throw new SecurityException("Invalid user or password entered.");
-            }
 
             if (enforcePassword)
             {