Http post error: An existing connection was forcibly closed by the remote host

Question

I realise there have been a number of similar posts to this but I haven\'t found a solution yet. Am trying to post some xml to an MPI gateway but keep getting the following

Answer 1

Slightly better perhaps:

System.Net.ServicePointManager.SecurityProtocol = System.Net.ServicePointManager.SecurityProtocol | System.Net.SecurityProtocolType.Tls12;