Getting System.Net.Http.HttpRequestException

[stesvis]

Hello, several times when I call PushSendAsync I get exceptions such as:

System.Net.Http.HttpRequestException An error occurred while sending the request. Void Throw() WebException The underlying connection was closed: An unexpected error occurred on a send. System.IO.Stream EndGetRequestStream(System.IAsyncResult, System.Net.TransportContext ByRef) IOException Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. Void EndWrite(System.IAsyncResult) SocketException An existing connection was forcibly closed by the remote host Int32 EndReceive(System.IAsyncResult)

What could cause this?