An existing connection was forcibly closed by the remote host

API and Webhooks
1

I have a C# code that creates a meeting:
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Method = method;
request.ContentType = “application/json”;
request.ContentLength = bytes.Length;
Stream dataStream = request.GetRequestStream();

On Windows Server 2019 Standard this code works fine in a console application and in a web application (IIS Version 1809).
On Windows 10 Pro this code works fine in the console application. In the web application (IIS Version 1809) I get an error:
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.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.ForceAuthentication(Boolean receiveFirst, Byte buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
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.GetRequestStream(TransportContext& context)
at System.Net.HttpWebRequest.GetRequestStream()

Which App Type (OAuth / Chatbot / JWT / Webhook)?
JWT

Which Endpoint/s?
url = https://api.zoom.us/v2/users/{userId}/meetings
method = POST

2

Hey @shamil_sayfutdinov,

Please check these threads to see if they answer your question:

https://devforum.zoom.us/search?q=An%20existing%20connection%20was%20forcibly%20closed%20by%20the%20remote%20host

Thanks,
Tommy

1 Like
3

Thank you!

This advice helped:

Enable strong cryptography in your local machine or server in order to use TLS1.2 because by default it is disabled so only TLS1.0 is used.
To enable strong cryptography , execute these commande in PowerShell with admin privileges:
Set-ItemProperty -Path ‘HKLM:\SOFTWARE\Wow6432Node\Microsoft.NetFramework\v4.0.30319’ -Name ‘SchUseStrongCrypto’ -Value ‘1’ -Type DWord
Set-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft.NetFramework\v4.0.30319’ -Name ‘SchUseStrongCrypto’ -Value ‘1’ -Type DWord

4

Thank you for sharing your solution @shamil_sayfutdinov! :slight_smile:

-Tommy