Hello, I've been dealing with problems connecting to Oracle database with Toad for a few days. When I solve one error, another comes :) The error I'm dealing with right now is ORA-12514: TNS: no listener. For this error, I connect to the Linux server where I installed the Oracle database and write the lsnrctl command using the oracle user. When I check it with the status command, the errors in the picture appear. When I type the startup command, it says "The listener rsupports no services". When I try to connect with Toad after these steps, I get a different error. New error: ORA-12514: TNS:listener does not currently know of service requested in connect descriptor. Can anyone comment on this error? I shared screenshots of listener.ora, sqlnet.ora and tnsnames.ora files respectively. I would really appreciate if anyone can help. Best regards.