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JDBC Connection to the Database Using VPN Fails with ORA-12516 (Doc ID 2977802.1)

Last updated on OCTOBER 05, 2023

Applies to:

JDBC - Version 19.3 and later
Information in this document applies to any platform.


Java application using Oracle JDBC to connect to a database via VPN fails with error:

ORA-12516, TNS:listener could not find available handler with matching protocol stack
at oracle.jdbc.driver.T4CConnection.logon(
at oracle.jdbc.driver.PhysicalConnection.<init>(
at oracle.jdbc.driver.T4CConnection.<init>(
at oracle.jdbc.driver.T4CDriverExtension.getConnection(
at oracle.jdbc.driver.OracleDriver.connect(



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