Check that the propagation and/or apply processes are started.
v$propagation_sender will show you the state of the propagation
V$streams_apply_reader will show you the status of the apply reader.
If the propagation is not started, use dbms_propagation_adm.start_propagation('propagation_name') to get it started
If the apply is not started, use dbms_apply_adm.start_apply('apply_name') to get it started.