Cannot read property 'validationConfig' of undefined

[EASemashko]

Hello, I get this error on one my projects, I can't find the reason.
Please explain me how to fix it.

This code raises it

a.fn.validate = function (b, c, d) {
var e = a.extend({}, a.formUtils.LANG, d || {});
this.each(function () {
var d = a(this), f = d.closest("form").get(0).validationConfig || {}; (ERROR RAISES HERE)
d.one("validation", function (a, c) {
"function" == typeof b && b(c, this, a)
}), d.validateInputOnBlur(e, a.extend({}, f, c || {}), !0)
})

[victorjonsson]

Let me know if this causes you any more problems