Do you mean the Tick History REST API? If so, there is a series of how to setup Tick History REST API with R Language articles as following:
in Part - 2
r <- GET(url,add_headers(prefer = "respond-async",Authorization = token))
a<-content(r, "parsed", "application/json", encoding="UTF-8")
List of 2
$ @odata.context: chr "https://hosted.datascopeapi.reuters.com/RestApi/v1/$metadata#UserPackages"
$ value : list()
The list is empty for me. Could you help me a solve for the same/any particular reason this is happening ?