Intermittent - An existing connection was forcibly closed by the remote host - ExecuteQuery()

Hello,

I have run the following code against our SharePoint Online, from several servers and local PCs and I get an intermittent error. It works on a server for a while, and then fails on the same server for a while:

IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.

Is this my issue or an issue with SharePoint Online?

Using .net framework 4.7.2, nuget Microsoft.SharePointOnline.CSOM package 16.1.21312.12000

         static void Main(string[] args)
        {
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
.
.
           string webUrl = "https://tenant.sharepoint.com/sites/SandBox";
           using (Microsoft.SharePoint.Client.ClientContext ctx =
                new Microsoft.SharePoint.Client.ClientContext(webUrl))
            {
                SecureString securePassword = new NetworkCredential("", "pass").SecurePassword;
                ctx.Credentials = new SharePointOnlineCredentials("user@tenant.onmicrosoft.com", securePassword);
                Web web = ctx.Web;
                ctx.Load(web, w => w.Title, w => w.Description);
                ctx.ExecuteQuery();
            }

 Unhandled Exception: System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send.
---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
--- End of inner exception stack trace ---
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.FixedSizeReader.ReadPacket(Byte[] buffer, Int32 offset, Int32 count)
at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
at System.Net.TlsStream.CallProcessAuthentication(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)
at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.ConnectStream.WriteHeaders(Boolean async)
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.SharePoint.Client.Idcrl.SharePointOnlineAuthenticationProvider.GetIdcrlHeader(Uri url, Boolean alwaysThrowOnFailure, EventHandler`1 executingWeb
Request)
at Microsoft.SharePoint.Client.Idcrl.SharePointOnlineAuthenticationProvider.GetAuthenticationCookie(Uri url, String username, SecureString password, Boolean alwaysThrowOnFailure, eventHandler`1 executingWebRequest)
at Microsoft.SharePoint.Client.SharePointOnlineCredentials.GetAuthenticationCookie(Uri url, Boolean refresh, Boolean alwaysThrowOnFailure)
at Microsoft.SharePoint.Client.ClientRuntimeContext.SetupRequestCredential(ClientRuntimeContext context, HttpWebRequest request)
at Microsoft.SharePoint.Client.SPWebRequestExecutor.GetRequestStream()
at Microsoft.SharePoint.Client.ClientContext.GetWebRequestExecutor()
at Microsoft.SharePoint.Client.ClientContext.GetFormDigestInfoPrivate()
at Microsoft.SharePoint.Client.ClientContext.EnsureFormDigest()
at Microsoft.SharePoint.Client.ClientContext.ExecuteQuery()
at PCS.ConsoleApp.SPPermissions.Program.Main(String[] args)