Why does the server return net::ERR_CONNECTION_CLOSED on ajax request?

Question

AJAX

On localhost, everything works fine, this problem got out on the server. Laravel/vue project. Ajax request code:

var firstHalf =  this.menu.slice(0, 21);
                var secondHalf =  this.menu.slice(21);
                var result = [firstHalf,secondHalf];
                this.isLoading = true;
                for (let i = 0; i < result.length; i++) {
                    let statusCode = 200;
                    axios({
                        method: "post",
                        url: "/admin/menu/addMenu/",
                        header: {
                            "X-CSRF-TOKEN": $('meta[name="csrf-token"]').attr("content")
                        },
                        params: {
                            menu: result[i],
                            startDate: this.selectedDate,
                            order: i + 1
                        }
                    }).then(response => {
                        console.log("ajax")
                        console.log(response.status);
                        console.log(response);
                        if (i+1>= result.length) {
                            this.message = response.data.message;
                            this.modalShow = true;
                            this.isLoading = false;
                            return;
                        }
                    });
                }

Answer 1

Usually this means that the server does not give a response at all, or, well, it interrupts the connection due to broken headers, respectively, first of all we try to turn off everything except the request itself, then check if there is one at all and whether the corresponding route is responding ... well, check if there is anything at all then in

"X-CSRF-TOKEN": $('meta[name="csrf-token"]').attr("content")