apollo: Why does the "Planning::RunOnce()" functon in the "planning" module always give a failed initialization?

I use the “demo_2.0.bag” data (located in the directoryapollo/docs/demo_guide to test the “planning” module", but the log file “planning.INFO” always gives the following failed initialization information:

W0205 18:59:46.826961  9508 reference_line_provider.cc:268] Reference line is NOT ready.
E0205 18:59:46.827069  9508 frame.cc:128] Failed to create reference line
E0205 18:59:46.827091  9508 frame.cc:268] Failed to init reference line info
E0205 18:59:46.827103  9508 planning.cc:66] failed to init frame
E0205 18:59:46.827193  9508 planning.cc:265] Init frame failed

Could you tell me the reason? Here is my steps:

# ${APOLLO_HOME} is the root directory of Apollo project. 
cd ${APOLLO_HOME}
bash docker/scripts/dev_start.sh
bash docker/scripts/dev_into.sh
bash scripts/bootstrap.sh
rosbag play -l docs/demo_guide/demo_2.0.bag

I have tried the “planner_type : EM” and “planner_type : RTK” choices both in the configuration file: planning_config.pb.txt(located in the directory apollo/modules/planning/conf). I also turned on the “routing” and “planning” module and sent a default routing request in the Dreamview page .