..The underlying connection was closed: An unexpected error occurred on a receive

Question

I have the following code:

private Uri currentUri;

private void Form1_Load(object sender, EventArgs e)
{
    currentUri = new Uri(@\"http://www.stackoverflo         


        

Answer 1

My Hosting server block requesting URL And code site getting the same error 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

After a lot of time spent and apply the following step to resolve this issue

1. Added line before the call web URL

   ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;

2. still issue not resolve then I upgrade .net version to 4.7.2 but I think it's optional

3. Last change I have checked my hosting server security level which causes to TLS handshaking for this used "https://www.ssllabs.com/ssltest/index.html" site
   and also check to request URL security level then I find the difference is requested URL have to enable a weak level Cipher Suites you can see in the below image

Now here are my hosting server supporting Cipher Suites

here is called if you have control over requesting URL host server then you can sync this both server Cipher Suites. but in my case, it's not possible so I have applied the following script in Windows PowerShell on my hosting server for enabling required weak level Cipher Suites.

Enable-TlsCipherSuite -Name "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384"
Enable-TlsCipherSuite -Name "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256"
Enable-TlsCipherSuite -Name "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA"
Enable-TlsCipherSuite -Name "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA"
Enable-TlsCipherSuite -Name "TLS_DHE_RSA_WITH_AES_256_CBC_SHA"
Enable-TlsCipherSuite -Name "TLS_DHE_RSA_WITH_AES_128_CBC_SHA"
Enable-TlsCipherSuite -Name "TLS_RSA_WITH_AES_256_GCM_SHA384"
Enable-TlsCipherSuite -Name "TLS_RSA_WITH_AES_128_GCM_SHA256"
Enable-TlsCipherSuite -Name "TLS_RSA_WITH_AES_256_CBC_SHA256"
Enable-TlsCipherSuite -Name "TLS_RSA_WITH_AES_128_CBC_SHA256"
Enable-TlsCipherSuite -Name "TLS_RSA_WITH_AES_256_CBC_SHA"
Enable-TlsCipherSuite -Name "TLS_RSA_WITH_AES_256_CBC_SHA"

after applying the above script my hosting server Cipher Suites level look like

Then my issue resolved.

Note: server security level downgrade is not a recommended option.