1 files changed, 3 insertions, 2 deletions
diff --git a/Emby.Server.Implementations/Session/WebSocketController.cs b/Emby.Server.Implementations/Session/WebSocketController.cs
index b986ffa1c..f9c6a13c6 100644
--- a/Emby.Server.Implementations/Session/WebSocketController.cs
+++ b/Emby.Server.Implementations/Session/WebSocketController.cs
@@ -8,6 +8,7 @@ using System.Linq;
 using System.Net.WebSockets;
 using System.Threading;
 using System.Threading.Tasks;
+using MediaBrowser.Common.Extensions;
 using MediaBrowser.Controller.Net;
 using MediaBrowser.Controller.Session;
 using MediaBrowser.Model.Net;
@@ -55,9 +56,9 @@ namespace Emby.Server.Implementations.Session
             connection.Closed += OnConnectionClosed;
         }
 
-        private void OnConnectionClosed(object sender, EventArgs e)
+        private void OnConnectionClosed(object? sender, EventArgs e)
         {
-            var connection = (IWebSocketConnection)sender;
+            var connection = sender as IWebSocketConnection ?? throw new ArgumentException($"{nameof(sender)} is not of type {nameof(IWebSocketConnection)}", nameof(sender));
             _logger.LogDebug("Removing websocket from session {Session}", _session.Id);
             _sockets.Remove(connection);
             connection.Closed -= OnConnectionClosed;