I am getting the same error. And I am not trying to use multipart for data, but a simple Get. Trying to consume a simple Rest, a call to a public server: https://open-ic.epic.com/FHIR/api/FHIR/DSTU2/metadata
Calling this endpoint in a browser or with Postman gives the expected response, no error. Calling this endpoint from the Outsystems platform (11.9.1) gives me the same type of error as reported by Andy. No need to ask for an OML, it can be reproduced on the development platform in the Logic/Integrations/Rest/Consume Rest API interface and simply using the endpoint URL mentioned above. See error message below.
Any suggestions? Thanks Denis.
The underlying connection was closed: An unexpected error occurred on a send.
[1] The underlying connection was closed: An unexpected error occurred on a send.
at System.Net.HttpWebRequest.GetResponse()
at sssantecure.CcEpicProduction.ActionGetMetadata(HeContext heContext, ICcEpicProductionCallbacks _callbacks, String inParamAccept, Int32 inParamProxy, String inParamEHR, STInstanceStructure& outParamResponse)
[2] Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
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)