Oracle : Ошибка ORA-12558

"TNS:protocol adapter not loaded"
*Cause: On some platforms (such as OS/2) protocol adapters are loaded at
run-time. If the shared library (or DLL) for the protocol adapter has not
been loaded, then this error is returned.
*Action: For further details, turn on tracing and reexecute the operation.
The trace file will have the name of the shared library (or DLL) that has
not been loaded.

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