I have encountered problem with Oracle Direct Connection tool. I have the correct host, port, service name, user name and password (the same configuration works with Toad), but Alteryx still complaints the service name is not found on tnsnames.ora (ORA-12154). Well, the reason to use Direct Connection is that I do not have admin rights on my computer to edit the file, so it seems this kind of problem can only be resolved by reaching out to our IT service to edit tnsnames.ora for me.