ORA-12154 error on oracle connection

Hi, 

I am trying to integrate Oracle database with One Identity Manager. I have created a ODBC data source on our job server which is cinnecting to oracle db successfully but when I am trying to use this data source while creating a native database connector synch project in 1IM, its giving me following error:

ORA-12154: TNS:could not resolve the connect identifier specified

I have searched the above error and found out about tnsnames.ora file which is present in my system and getting used in ODBC connection.

On the other hand if I try to connect without oracle client - it gives me following error:

ORA-03113: end-of-file on communication channel

Has anyone faced this issue? Any help please

Regards,

Priyank