ORA-12547: TNS:lost contact

I was schedule RMAN Backup through root user,
 root> crontab -e
After that Facing below error.

Recovery Manager: Release 11.1.0.7.0 - Production on Mon Aug 25 02:50:02 2014
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00554: initialization of internal recovery manager package failed
RMAN-04005: error from target database:
ORA-12547: TNS:lost contact


Solution:-

Use Database user to schedule Rman backup scripts.
 ora> crontab -e

Edit  below file:-
root> vi /etc/cron.allow



In this file enter your db_user name like below after that save it.
root
orauser


check cron.deny file.
root>cat /etc/cron.deny
if any entry in this file related to your user name remove it.

save it.
After that you can schedule Rman backup scripts throught Database user.

ora> crontab -e

its working fine.