ORA-12518: TNS:listener could not hand off client connection
 *Cause: The process of handing off a client connection to another process
 failed.
 *Action: Turn on listener tracing and re-execute the operation. Verify
 that the listener and database instance are properly configured for
 direct handoff.  If problem persists, call Oracle Support.
 *Comment: The problem can be worked around by configuring dispatcher(s)
 to specifically handle the desired presentation(s), and connecting
 directly to the dispatcher, bypassing the listener.