Oracle Message ORA-06131 - NETTCP: user access denied

ERRORNETTCP: user access denied
CAUSEThe hosts SQL*Net TCP/IP server rejected this connection request because the client user(name) does not have access privilege - as determined by the contents of the Username Mapping Table (UMT), a component of the hosts CONFIG.ORA.
ACTIONTo grant access, add appropriate entry to the hosts UMT.