A request works for a particular RIC. But the same request fails for another RIC for the same asset class. 
eg. for CLc1, I do get the expected time series output.  Attaching an R output: 
[1] "Request *************************************" 
{"Entity":{"E":["TimeSeries"],"W":{"rics":[["CLc1"]],"fields":[["*"]],"interval":["hour"],"startdate":["2017-01-01T05:30:00"],"enddate":["2017-12-27T15:00:00"]}}} 
[1] "Response *************************************" 
[1] "{\"timeseriesData\":[{\"dataPoints\":[[\"2017-05-28T23:00:00Z\",50.04,49.84,49.93,49.9,1596,7104],
.. <truncated> 
[1] "Response status *************************************" 
[1] 200
But for LCOc1, The same script does not seem to work. I get the following error: 
[1] "Request *************************************" 
{"Entity":{"E":["TimeSeries"],"W":{"rics":[["LCOc1"]],"fields":[["*"]],"interval":["hour"],"startdate":["2017-01-01T05:30:00"],"enddate":["2017-12-27T15:00:00"]}}} 
[1] "Response *************************************" 
[1] "{\"ErrorCode\":\"408\",\"Environment\":\"prod\",\"DataCenter\":\"STCP\",\"ErrorMessage\":\"Request timeout occured\",\"Inner\":\"System.Threading.Tasks.TaskCanceledException: A task was canceled.\\r\\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\\r\\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\\r\\n   at ThomsonReuters.Eikon.UDF.RequestProcessing.RequestSenderBase`1.<SendRequestAsync>d__5.MoveNext()\"}" 
[1] "Response status *************************************"
[1] 200