This relates to an unresolved issue with Go and SSL/TLS (golang/go#8265)

Self signed certs can cause RRP to return the following error: HTTP/1.1 400 tls: failed to parse certificate from server: x509: negative serial number

For example if you are using Fiddler (http://www.telerik.com/fiddler) to debug your web service/rest api requests via RRP, a self signed cert is used for decrypting HTTPS requests and can result in this error