ORA-12523 Connecting Via the Listener
(Doc ID 2313136.1)
Last updated on OCTOBER 20, 2017
Applies to:Oracle Net Services - Version 126.96.36.199 and later
Microsoft Windows x64 (64-bit)
In an environment where multiple databases are registered against a single listener.
Some connections via the listener fail with the following error:
ORA-12523: TNS:listener could not find instance appropriate for the client
In this case, the LOCAL_LISTENER setting for each instance might be specified differently.
One instance shows the HOST field populated with a hostname.
Another instance shows the HOST field populated by an ip address.
This is likely a new installation or a database has recently been created on this server.
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