ORA-12545: Connect failed because target host or object does not exist
 What causes this error?
An ORA-12545 error occurs when the client is not able to contact the listener on the node specified. For example: when the listener has not been started on the node, if the node address has been specified incorrectly, or a firewall blocks access.
 How to fix it
This message occurs when the listener on the remote node cannot be contacted.
Did you add the host name and IP in your DNS server?
You can try tracing the path or the route a connection is taking from the client to the server. If it encounters an error, then it returns the error stack which gives us more information when compared to an cryptic one line error.
Execute the following:
This will help you find the problem and fix it. The problem may fall into one of the following areas:
- Check TNSNAMES.ORA:
The TNSNAMES.ORA may contain a wrong address. Check the host and port have been specified correctly. Check the details against the LISTENER.ORA file.
- Check the remote node:
lsnrctl lsnrctl> status listener_name
listener_name is the name of the listener defined in the listener.ora file. If you have not changed the listener name, then it would be called LISTENER.
If the listener has not been started, start it with the command:
lsnrctl> start listener_name
You can check if the fix worked by executing tnsping. It should return an "OK" message if the TNSPING has been successful.