c# WebRequest error An existing connection was forcibly closed by the remote host
“An error occurred while making the HTTP request to https://<API endpoint>. This could be due to the fact that the server certificate is not configured properly with HTTP.SYS in the HTTPS case. This could also be caused by a mismatch of the security binding between the client and the server.” Inner exception was “ Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ” this happened to me when doing some HttpWebRequests and suddenly everything stopped working. apparently the server changed protocol to Tls1.2, and that caused all the mess. PLUS i was using .Net4 so no enum there, so here is the magic line for all you problems ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;