diff --git a/v2rayN/v2rayN/Handler/DownloadHandle.cs b/v2rayN/v2rayN/Handler/DownloadHandle.cs
index c2fb9914..5d4d3caf 100644
--- a/v2rayN/v2rayN/Handler/DownloadHandle.cs
+++ b/v2rayN/v2rayN/Handler/DownloadHandle.cs
@@ -4,6 +4,7 @@ using System.IO;
 using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
+using System.Net.Sockets;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
@@ -66,7 +67,11 @@ namespace v2rayN.Handler
             catch (Exception ex)
             {
                 //Utils.SaveLog(ex.Message, ex);
-                Error?.Invoke(this, new ErrorEventArgs(ex));
+                Error?.Invoke(this, new ErrorEventArgs(ex)); 
+                if (ex.InnerException != null)
+                {
+                    Error?.Invoke(this, new ErrorEventArgs(ex.InnerException));
+                }
             }
             return 0;
         }
@@ -104,7 +109,11 @@ namespace v2rayN.Handler
             {
                 Utils.SaveLog(ex.Message, ex);
 
-                Error?.Invoke(this, new ErrorEventArgs(ex));
+                Error?.Invoke(this, new ErrorEventArgs(ex)); 
+                if (ex.InnerException != null)
+                {
+                    Error?.Invoke(this, new ErrorEventArgs(ex.InnerException));
+                }
             }
         }
 
@@ -167,6 +176,10 @@ namespace v2rayN.Handler
             {
                 Utils.SaveLog(ex.Message, ex);
                 Error?.Invoke(this, new ErrorEventArgs(ex));
+                if (ex.InnerException != null)
+                {
+                    Error?.Invoke(this, new ErrorEventArgs(ex.InnerException));
+                }
             }
             return null;
         }
@@ -239,13 +252,35 @@ namespace v2rayN.Handler
                 return null;
             }
             var httpPort = LazyConfig.Instance.GetConfig().GetLocalPort(Global.InboundHttp);
-            var webProxy = new WebProxy(Global.Loopback, httpPort);
-            if (RunAvailabilityCheck(webProxy) > 0)
+            if (!SocketCheck(Global.Loopback, httpPort))
             {
-                return webProxy;
+                return null;
             }
 
-            return null;
+            return new WebProxy(Global.Loopback, httpPort);
+        }
+
+        private bool SocketCheck(string ip, int port)
+        {
+            Socket sock = null;
+            try
+            {
+                IPAddress ipa = IPAddress.Parse(ip);
+                IPEndPoint point = new IPEndPoint(ipa, port);
+                sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+                sock.Connect(point);
+                return true;
+            }
+            catch { }
+            finally
+            {
+                if (sock != null)
+                {
+                    sock.Close();
+                    sock.Dispose();
+                }
+            }
+            return false;
         }
     }
 }