Feb 06, 2015 02:58 PM|Lannie|LINK
Generic error, but usually connection problems
Things to check
Firewall (software and hardware) must allow traffic on the TCP port used by tnsnames.ora
Antivirus blocking applications
Lower level firewalls that can block specific applications
Wrong tns configuration or connection info
Missing Oracle client and Oracle Data Access on the IIS server
see if the oracle client on IIS server can connect to the database on the same account used by the applications
with a simple select table statement.
If using the Oracle Managed Driver, put a copy of tnsnames.ora in the application /BIn folder
but beware Oracle Managed Driver will not work in FIPS-140 enabled environment unless you are using Oracle 12c102 database and latest ODAC 12cR3 driver.
And many other things to look for.