Error while connecting to Oracle DB on server

Question

I am getting an error while trying to connect to oracle DB on the server throught Toad. The error message is :
ORA-12514: TNS:listener could not resolve Service_Name given in connect descriptor.
Everything was working fine till yesterday but today my server got restarted and i am not ablt to connect to DB. I tried tnsping as well and it is working fine:

TNS Ping Utility for 32-bit Windows: Version 9.2.0.1.0 - Production on 10-NOV-20 10 15:13:29

Copyright (c) 1997 Oracle Corporation. All rights reserved.

Used parameter files: c:\oracle\ora92\network\admin\sqlnet.ora

Used TNSNAMES adapter to resolve the alias Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (HOST = MY4D) (PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME =sim))) OK (80 msec)

I did lsnrctl start and it says Service OracleOraHome92TNSListener already running.

Still oracle throught toad is not working. Can anyone help me in solving this.

Answer 1

This error usually happens when your oracle services are not running. You will see the services by names "Oracle..TNSListener" and another service with name "OracleServicesim" in your services.msc. Check if both of them are running, or restart both those services. Then try to connect. It should work fine.