Oracle Database / Connections & Oracle Net
ORA-12504: supply the intended service in a connect request
A connection request that omits required service information can reach the listener and still be rejected. Compare the descriptor with a working supported example.
Environment and inputs: Oracle Database 19c baseline · SQL*Plus-compatible SQL unless RMAN, DGMGRL, ADRCI or a host shell is specified. Check release, patch level, edition and container first.
Start with this diagnostic
Use the stated SQL, RMAN, DGMGRL or host shell and replace sample names with approved targets. DBA and V$ views need authorized catalog access in the correct container. Do not grant broad privileges for an example.
lsnrctl services LISTENERRead the result
The server-side listing identifies registered service names, which must be compared with the client's actual CONNECT_DATA. It does not choose the correct business service for you.
Resolve and verify
Obtain the intended service name from the DBA and correct the application's descriptor or Easy Connect syntax. Confirm the target after login with session context.
Operational precautions
Do not rely on a default service that happens to route to a different PDB or environment.