Some common reasons that setup/connection issues occur are:
The library path environment variable is not set correctly.
Note: The 32-bit and 64-bit Autonomous REST Connectors require that you set the library path environment for your operating system to the directory containing your 32-bit JVM’s libjvm.so file, and that directory’s parent directory before using the driver.
The library path environment variable is:
32-bit Drivers
PATH on Windows
LD_LIBRARY_PATH on Linux
64-bit Drivers
PATH on Windows
LD_LIBRARY_PATH on Linux
The database and/or listener are not started.
The ODBCINI environment variable is not set correctly for the ODBC drivers on Linux.
The ODBC driver’s connection attributes are not set correctly in the system information file on Linux. See "Data Source Configuration on Linux" for more information. For example, the host name or port number are not correctly configured. See "Connection Option Descriptions" for a list of connection string attributes that are required for each driver to connect properly to the underlying database.
For Linux users: See "Configuring the Product on Linux" for more information. See also "The Test Loading Tool" for information about a helpful diagnostic tool.
The library path environment variable is not set correctly.