Set the debug mode to On and then try again and see the error logs. Share those Logs here.
DATABASE ERROR : Could not write employee data
error code : 1366
error message : Incorrect integer value: '' for column `u9619550_fron771`.`0_employee`.`emp_id` at row 1
sql that failed was : INSERT INTO 0_employee VALUES ('', 'inge', 'indra', '0', '', '', '', '1974-01-19', '', '2021-01-01', '0', '0', '', '')
/home/u9619550/public_html/latihan/includes/errors.inc:208: trigger_error('DATABASE ERROR : Could not write employee data
error code : 1366
error message : Incorrect integer value: '' for column `u9619550_fron771`.`0_employee`.`emp_id` at row 1
sql that failed was : INSERT INTO 0_employee VALUES ('', 'inge', 'indra', '0', '', '', '', '1974-01-19', '', '2021-01-01', '0', '0', '', '')
','256')
/home/u9619550/public_html/latihan/includes/errors.inc:236: display_db_error('Could not write employee data','INSERT INTO 0_employee VALUES ('', 'inge', 'indra', '0', '', '', '', '1974-01-19', '', '2021-01-01', '0', '0', '', '')','')
/home/u9619550/public_html/latihan/includes/db/connect_db_mysqli.inc:91: check_db_error('Could not write employee data','INSERT INTO 0_employee VALUES ('', 'inge', 'indra', '0', '', '', '', '1974-01-19', '', '2021-01-01', '0', '0', '', '')','1')
/home/u9619550/public_html/latihan/modules/FrontHrm/includes/db/employee_db.inc:56: db_query('INSERT INTO 0_employee VALUES ('', 'inge', 'indra', '0', '', '', '', '1974-01-19', '', '2021-01-01', '0', '0', '', '')','Could not write employee data')
/home/u9619550/public_html/latihan/modules/FrontHrm/manage/employee.php:353: write_employee('','inge','indra','0','','','','19/01/1974','','01/01/2021','0','0','','')