API request returns error invalid RIC for get_timeseries

The following code throws me an error. At the same time, Excel add-on returns a time-series for the same RIC and dates.

import eikon as ek

df = ek.get_timeseries("LLCCS30",
                       start_date="2018-06-01",
                       end_date="2018-06-10",
                       fields='CLOSE')

The error is the following:

Error with LLCCS30: Invalid RIC

LLCCS30: Invalid RIC |

Error code -1 | LLCCS30: Invalid RIC |

How should the error be handled?