Timeseries data request gets no records on specific days

Using this code I expect to subscribe to a 1-minute interval for the ask quote on RIC DE200443845= for the 30th May:

            request = timeSeries.SetupDataRequest("DE200443845=")
                .WithView("ASK")
                .WithAllFields()
                .WithInterval(CommonInterval.Intraday1Minute)
                .From(new DateTime(2019, 5, 30))
                .To(new DateTime(2019, 5, 31))
                .OnDataReceived(DataReceivedCallback)
                .CreateAndSend();

However no records are returned in the DataReceivedCallback(DataChunk chunk) method.

What bothers me here is that:

1. When I set the date to:

                .From(new DateTime(2019, 5, 29))
                .To(new DateTime(2019, 5, 30))

I get all the ask quotes for the 29th May as expected so that I can assume the code to be fine.

2. When I use the XL EIKON Add-In with this function:

=RHistory("DE200443845=";"ASK.Close";"START:30-May-2019 END:30-May-2019 INTERVAL:1M";;"TSREPEAT:NO CH:Fd";$Z$1)

I do get all the 68 ask quotes for the instrument for the 30th May. So the ask quote data seems to exist.

That makes me wonder why I do not get the ask quotes for the 30th May for DE200443845= using the EIKON .NET API. Thanks in advance for your help.