This is probably due to wrong tcp/ip address in tnsnames.ora
or the server is on a separate network from the clients.
Try to ping with the address in the tnsnames.ora.
If it does not work check the tcp/ip address or call the network
administrator.
If it works try tnsping with the connection string
Samar,
This might be due to failure in resolving hostname to ip address. You can try adding
the servers ip address and hostname to the hosts file on client machine. This file
will be in c:\windows\system32\drivers\etc\hosts. Add the entry of servers ip followed
by server's hostname.
Cheers,
If you're using tnsnames.ora to connect to the database, make sure the
tnsnames.ora file on the client matches the listener.ora file on the server.
Also check the sqlnet.ora file to make sure tnsnames is specified first.
Also, after you verified that, do a tnsping to the target instance from t
