ORA-12519: TNS :no appropriate service handler found .

SQL> show parameter processes

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

aq_tm_processes                       integer     1

db_writer_processes                   integer     1

gcs_server_processes                  integer     0

global_txn_processes                  integer     1

job_queue_processes                   integer     40

log_archive_max_processes             integer     4

processes                             integer     300

SQL> alter system set processes=500 scope=spfile;

System altered.

Restart database after this operation.