CRITICAL: Failed to connect to database instance: ORA-12537: TNS:connection closed (DBD ERROR: OCIServerAttach)

CRITICAL: Failed to connect to database instance: ORA-12537: TNS:connection closed (DBD ERROR: OCIServerAttach)

The DB alert log show max processes exceeded.

ORA-00020: maximum number of processes (150) exceeded
ORA-20 errors will not be written to the alert log for
the next minute. Please look at trace files to see all
the ORA-20 errors.
Incremental checkpoint up to RBA [0x6c.3340f.0], current log tail at RBA [0x6c.34e88.0]
ORA-00020: maximum number of processes (150) exceeded
ORA-00020: maximum number of processes (150) exceeded
ORA-20 errors will not be written to the alert log for
ORA-20 errors will not be written to the alert log for
the next minute. Please look at trace files to see all
the next minute. Please look at trace files to see all
the ORA-20 errors.
the ORA-20 errors


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     10
log_archive_max_processes            integer     4
processes                            integer     150
SQL> show parameter sessions;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
java_max_sessionspace_size           integer     0
java_soft_sessionspace_limit         integer     0
license_max_sessions                 integer     0
license_sessions_warning             integer     0
sessions                             integer     248
shared_server_sessions               integer
SQL>

===========================


SQL> alter system set processes=300 scope=both;

alter system set processes=300 scope=both
                 *
ERROR at line 1:
ORA-02095: specified initialization parameter cannot be modified


SQL> alter system set processes=300 scope=spfile;

System altered.

SQL> alter system set sessions=496 scope=spfile;

System altered.


- Bounce the database for changes to be effective