jquery error

Hi,
I use plugin “Conditional Fields for Contact Form 7” with a personnal theme developped by a webagency.
The plugin doesn’t work due to a error javascript :

scripts_es6.js:892 Uncaught TypeError: jQuery(...).ajaxComplete is not a function
    at Module../js/scripts_es6.js (scripts_es6.js:892:18)
    at __webpack_require__ (bootstrap:19:1)
    at Object.0 (scripts.js?ver=2.0.9:4003:18)
    at __webpack_require__ (bootstrap:19:1)
    at bootstrap:83:1
    at bootstrap:83:1
./js/scripts_es6.js	@	scripts_es6.js:892
__webpack_require__	@	bootstrap:19
0	@	scripts.js?ver=2.0.9:4003
__webpack_require__	@	bootstrap:19
(anonymous)	@	bootstrap:83
(anonymous)	@	bootstrap:83

Coudl you help me please ?

Thx