diff --git a/OpenSim/Framework/RestClient.cs b/OpenSim/Framework/RestClient.cs
index a87a52e434..d0dfc9d060 100644
--- a/OpenSim/Framework/RestClient.cs
+++ b/OpenSim/Framework/RestClient.cs
@@ -269,6 +269,15 @@ namespace OpenSim.Framework
                     request.Headers.ExpectContinue = false;
                     request.Headers.TransferEncodingChunked = false;
 
+                    //if (keepalive)
+                    {
+                        request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
+                        request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                        request.Headers.ConnectionClose = false;
+                    }
+                    //else
+                    //    request.Headers.TryAddWithoutValidation("Connection", "close");
+
                     cancellationToken = new CancellationTokenSource(TimeSpan.FromSeconds(DefaultTimeout));
 
                     if (WebUtil.DebugLevel >= 3)
diff --git a/OpenSim/Framework/WebUtil.cs b/OpenSim/Framework/WebUtil.cs
index 29b24a1de0..101d9c7ff0 100644
--- a/OpenSim/Framework/WebUtil.cs
+++ b/OpenSim/Framework/WebUtil.cs
@@ -411,6 +411,7 @@ namespace OpenSim.Framework
                 {
                     request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
                     request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                    request.Headers.ConnectionClose = false;
                 }
                 else
                     request.Headers.TryAddWithoutValidation("Connection", "close");
@@ -560,6 +561,7 @@ namespace OpenSim.Framework
                 //{
                 //    request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
                 //    request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                //    request.Headers.ConnectionClose = false;
                 //}
                 //else
                     request.Headers.TryAddWithoutValidation("Connection", "close");
@@ -1178,6 +1180,7 @@ namespace OpenSim.Framework
                 {
                     request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
                     request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                    request.Headers.ConnectionClose = false;
                 }
                 else
                     request.Headers.TryAddWithoutValidation("Connection", "close");
@@ -1273,6 +1276,7 @@ namespace OpenSim.Framework
                 {
                     request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
                     request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                    request.Headers.ConnectionClose = false;
                 }
                 else
                     request.Headers.TryAddWithoutValidation("Connection", "close");
@@ -1412,6 +1416,7 @@ namespace OpenSim.Framework
                 {
                     request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
                     request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                    request.Headers.ConnectionClose = false;
                 }
                 //else
                 //    request.Headers.TryAddWithoutValidation("Connection", "close");
@@ -1535,6 +1540,7 @@ namespace OpenSim.Framework
                 {
                     request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
                     request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                    request.Headers.ConnectionClose = false;
                 }
                 //else
                 //    request.Headers.TryAddWithoutValidation("Connection", "close");
diff --git a/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs b/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs
index 17053cd8ab..5b37f4520e 100644
--- a/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs
+++ b/OpenSim/Services/Connectors/Inventory/XInventoryServicesConnector.cs
@@ -30,6 +30,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Net;
+using System.Net.Http;
 using System.Reflection;
 using Nini.Config;
 
@@ -40,6 +41,7 @@ using OpenSim.Services.Interfaces;
 using OpenSim.Server.Base;
 using OpenMetaverse;
 using System.Text;
+using System.Threading;
 
 namespace OpenSim.Services.Connectors
 {
@@ -747,54 +749,59 @@ namespace OpenSim.Services.Connectors
         {
             if (WebUtil.DebugLevel >= 3)
                 m_log.Debug($"[XInventory]: HTTP OUT SynchronousRestForms POST to {m_InventoryURL}");
-
-            int tickstart = Util.EnvironmentTickCount();
-
-            HttpWebRequest request;
-            try
+            if (string.IsNullOrEmpty(obj))
             {
-                request = (HttpWebRequest)WebRequest.Create(m_InventoryURL);
-                request.Method = "POST";
-                if (m_requestTimeoutSecs > 0)
-                    request.Timeout = m_requestTimeoutSecs * 1000;
-                if (m_Auth is not null)
-                    m_Auth.AddAuthorization(request.Headers);
-
-                request.AllowWriteStreamBuffering = false;
-                request.ContentType = "application/x-www-form-urlencoded";
-            }
-            catch (Exception e)
-            {
-                m_log.Info($"[XInventory]: Error creating POST request to {m_InventoryURL}: {e.Message}");
-                throw;
-            }
-
-            int sendlen;
-            try
-            {
-                byte[] data = Util.UTF8NBGetbytes(obj);
-                sendlen = data.Length;
-                request.ContentLength = sendlen;
-
-                using (Stream requestStream = request.GetRequestStream())
-                    requestStream.Write(data, 0, sendlen);
-                data = null;
-            }
-            catch (Exception e)
-            {
-                m_log.Info($"[XInventory]: Error sending POST request to {m_InventoryURL}: {e.Message}");
-                throw;
+                m_log.Warn($"[XInventory]: empty post data");
+                return new Dictionary<string, object>();
             }
 
             Dictionary<string, object> respDic = null;
+            int ticks = Util.EnvironmentTickCount();
+            int sendlen = 0;
             int rcvlen = 0;
+            HttpResponseMessage responseMessage = null;
+            HttpRequestMessage request = null;
+            CancellationTokenSource cancellationToken = null;
             try
             {
-                using WebResponse resp = request.GetResponse();
-                if (resp.ContentLength != 0)
+                HttpClient client = WebUtil.SharedHttpClientWithRedir;
+
+                request = new(HttpMethod.Post, m_InventoryURL);
+
+                m_Auth?.AddAuthorization(request.Headers);
+
+                //if (keepalive)
                 {
-                    rcvlen = (int)resp.ContentLength;
-                    respDic = ServerUtils.ParseXmlResponse(resp.GetResponseStream());
+                    request.Headers.TryAddWithoutValidation("Keep-Alive", "timeout=30, max=10");
+                    request.Headers.TryAddWithoutValidation("Connection", "Keep-Alive");
+                    request.Headers.ConnectionClose = false;
+                }
+                //else
+                //    request.Headers.TryAddWithoutValidation("Connection", "close");
+
+                request.Headers.ExpectContinue = false;
+                request.Headers.TransferEncodingChunked = false;
+
+                if (m_requestTimeoutSecs > 0)
+                    cancellationToken = new CancellationTokenSource(TimeSpan.FromSeconds(m_requestTimeoutSecs));
+
+                byte[] data = Util.UTF8NBGetbytes(obj);
+                sendlen = data.Length;
+
+                request.Content = new ByteArrayContent(data);
+                request.Content.Headers.TryAddWithoutValidation("Content-Type", "application/x-www-form-urlencoded");
+                request.Content.Headers.TryAddWithoutValidation("Content-Length", sendlen.ToString());
+
+                if (cancellationToken is null)
+                    responseMessage = client.Send(request, HttpCompletionOption.ResponseHeadersRead);
+                else
+                    responseMessage = client.Send(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken.Token);
+                responseMessage.EnsureSuccessStatusCode();
+
+                if ((responseMessage.Content.Headers.ContentLength is long contentLength) && contentLength != 0)
+                {
+                    rcvlen = (int)contentLength;
+                    respDic = ServerUtils.ParseXmlResponse(responseMessage.Content.ReadAsStream());
                 }
             }
             catch (Exception e)
@@ -802,11 +809,17 @@ namespace OpenSim.Services.Connectors
                 m_log.Info($"[XInventory]: Error receiving response from {m_InventoryURL}: {e.Message}");
                 throw;
             }
-
-            int tickdiff = Util.EnvironmentTickCountSubtract(tickstart);
-            if (tickdiff > WebUtil.LongCallTime)
+            finally
             {
-                m_log.Info($"[XInventory]: POST {m_InventoryURL} took {tickdiff}ms {sendlen}/{rcvlen}bytes");
+                request?.Dispose();
+                responseMessage?.Dispose();
+                cancellationToken?.Dispose();
+            }
+
+            ticks = Util.EnvironmentTickCountSubtract(ticks);
+            if (ticks > WebUtil.LongCallTime)
+            {
+                m_log.Info($"[XInventory]: POST {m_InventoryURL} took {ticks}ms {sendlen}/{rcvlen}bytes");
             }
 
             return respDic ?? new Dictionary<string, object>();