APPS R12.1.1 post cloning for Database Tier error - ORA-12547: TNS:lost contact

Introduction:

On post cloning of database tier of APPS R12.1.1 , it ended with errors "ORA-12547: TNS:lost contact"

Resolution:

Following were the errors which we got in ApplyDbTier.
===============
LD_LIBRARY_PATH : /erptst/TST/db/tech_st/11.1.0/lib:/usr/dt/lib:/usr/openwin/lib:/erptst/TST/db/tech_st/11.1.0/ctx/lib:/erptst/TST/db/tech_st/11.1.0/lib32

Executable : /erptst/TST/db/tech_st/11.1.0/bin/sqlplus

The log information will be written to
/erptst/TST/db/tech_st/11.1.0/appsutil/log/TST_testmachine/adcrdb_TST.txt


Creating the control file for TST_testm1 database ...


SQL*Plus: Release 11.1.0.7.0 - Production on Mon Oct 10 16:00:59 2011

Copyright (c) 1982, 2008, Oracle. All rights reserved.

ERROR:
ORA-12547: TNS:lost contact


ORA-12547: TNS:lost contact
ERROR:
ORA-12547: TNS:lost contact


ORA-12547: TNS:lost contact
SP2-0640: Not connected
==============================

We tried to connect from sqlplus but after few seconds of wait it again gave the same error.

We checked the inventory location and permission and it was all ok.

We tried again the post clone, but this time we choose the different SID as CLN and gave the different port number, previously it was 01 and this time we chose 79. And this time the post clone went successful without any errors, this is so weird, but this is just what happened!