Cause:- The most frequent cause is the smaller value of the parameter "PROCESSES" set in Oracle, which needs to be increased in order to solve this issue PROCESSES specifies the maximum number of operating system user processes that can simultaneously connect to Oracle Value of this parameter can be fetched using query:- SQL> show parameter process SQL>SELECT name, value FROM gv$parameter WHERE isdefault = 'FALSE'; Solution:- Login as a system DBA ( conn sys as sysdba ) SQL> alter system set processes=200 scope=spfile Restart the oracle database and the newly entered value for processes parameter will come into effect.