SQL> show parameter process

NAME                                 TYPE                             VALUE
------------------------------------ -------------------------------- ------------------------------
aq_tm_processes                      integer                          1
cell_offload_processing              boolean                          TRUE
db_writer_processes                  integer                          6
gcs_server_processes                 integer                          0
global_txn_processes                 integer                          1
job_queue_processes                  integer                          1000
log_archive_max_processes            integer                          4
processes                            integer                          1000
SQL> select * from v$resource_limit where resource_name='processes';

RESOURCE_NAME                  CURRENT_UTILIZATION MAX_UTILIZATION INITIAL_AL LIMIT_VALU
------------------------------ ------------------- --------------- ---------- ----------
processes                                      160             519       1000       1000

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.