There is an important parameter is "processes" and this specifies the maximum number of operating system user processes that can simultaneously connect to Oracle.
I am sure you can increase this parameter more than 150 (current by default is 150) or more, but maximum limit depend on operation systems MEM or HDD space.
To increase, login to
sqlplus "/ as sysdba"
SELECT COUNT(*) FROM v$session;
SHOW PARAMETER SESSIONS --this return current value use below command increase this
ALTER SYSTEM SET SESSIONS= SCOPE=SPFILE;
SHOW PARAMETER PROCESSES --this return current value use below command increase this
ALTER SYSTEM SET PROCESSES= SCOPE=SPFILE;
shutdown immediate;
startup;
<< (*_*) >>
