ORA-12522: TNS:listener could not find available

admin

ORA-12522:TNS:listener could not find available instance with given INSTANCE_
ROLE
Cause: There are not any available and appropriate databaseinstances registered
with the listener, that are part of the service identified by SERVICE_NAMEgiven
in the connect descriptor and that have the specified INSTANCE_ROLE (and
INSTANCE_NAME, if specified).
Action: Checkto make sure that the INSTANCE_ROLE specified is correct. Run
"lsnrctl services" to ensure that the instance(s) have registeredwith the listener and
that they are ready to accept connections.