All Oracle errors
ORA-12514net

Listener does not know of service

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

Why it happens

The listener is running but the SERVICE_NAME used is not registered by any instance — wrong service name, the instance is down, or dynamic registration never fired.

How to fix it

Use the correct SERVICE_NAME from the tnsnames, check the database is up, or register statically in listener.ora. Query lsnrctl services to list the actual service names.

A note on ORA-12514

This entry is part of a hand-curated set of ORA-, FRM-, REP- and TNS- codes that actually turn up in production Oracle estates — SQL*Plus, APEX, 19c/21c, ODP.NET apps, Oracle Forms 6i/12c and Reports included. The message text above is the canonical wording; the cause and fix are written in plain language so a developer or DBA can act without digging through pages of Oracle reference docs first.

Codes outside this list of 44 are far less common. If you hit one, the official Oracle error reference and your instance's alert or listener log remain the authoritative source.

Related net errors

ORA-03113 · End-of-file on communication channel ORA-03114 · Not connected to ORACLE ORA-12154 · TNS cannot resolve connect identifier

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