ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

Cause:
The listener received a request to establish a connection to a database or other service. The connect descriptor received by the listener specified a service name for a service (usually a database service) that either has not yet dynamically registered with the listener or has not been statically configured for the listener. This may be a temporary condition such as after the listener has started, but before the database instance has registered with the listener.


Solution:
1. Check your tnsnames.ora as shown in my post on ora-12154.
2. Check if your listener service are on, if not start your lisnter using lsnrctl. More information on this take a look at the same post at ora-12154. 
3. Check if the service is on using command line lsnrctl services
4. Check your listener.log 

Posted in: Ora Error, ORA-12514, Oracle Listener