Check your local TNSNAMES.ORA File
- Make sure that your listener is listening for the same service name that you are using.
- Your service name might have an alias, so check for global (world) entries and local entries.
Check your global_name setting with this SQL:
select * from global_name;
The query value should match your init.ora parms for db_name and db_domain
- Can you post the output of lsnrctl status command on your server side?
- Can you post the content of tnsnames.ora and sqlnet.ora in your client side?
Check the listener status in server
Post the listener.ora and clients tnsnames.ora entry??