First look for a file located under $ORACLE_HOME/NETWORK/LISTENER.LOG.  This should provide with more info on why the listener fails to start up.

The listener can be restarted from DOS prompt using the following steps:

cd to $ORACLE_HOME\bin directory and run LSNRCTL*.exe, then from LSNRCTL> prompt issue START command like the following

LSNRCTL> start

Related Issues/Questions:
nhStartDb failed with unable to start TNS Listener
How to start TNS Listener on a Microsoft Windows system
Error from nhStartDb or startup: "ORA-12560: TNS:protocol adapter error SVRMGR> Password: ORA-12560: TNS:protocol adapter error"
Oracle listener fails to start up

Problem Environment:
eHealth 5.x
Oracle


(Legacy KB ID CNC TS16176 )

Release:
Component: EHCON