Ошибка в консоли Error during WebSocket handshake: Unexpected response code: 502

Запускаю приложение Flask на сервере Nginx + UWSGI на Ubuntu. При открытии страницы /settings_dev в консоли вылазит ошибка

WebSocket connection to 'ws://185.151.245.211/socket.io/?EIO=3&transport=websocket&sid=732f1a47c60244c5bc9ef33d5bee9d74' failed: Error during WebSocket handshake: Unexpected response code: 502

Файл /etc/nginx/sites-available/projectnew:

server {
    listen 80;
    server_name 185.151.245.211 www.185.151.245.211;

    location / {
        include uwsgi_params;
        uwsgi_pass unix:/home/sammy/projectnew/projectnew.sock;
    }

    location /socket.io/ {
        proxy_http_version 1.1;
        proxy_buffering off;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        include uwsgi_params;
        uwsgi_pass unix:/home/sammy/projectnew/projectnew.sock;
    }
}

Файл settings_dev.js:

function editDevice(dev_code, dev_name, dev_path_img, dev_id){
    console.log("Edit");
    var field_dev1 = document.getElementById("field_dev_edit1");
    var field_dev2 = document.getElementById("field_dev_edit2");
    var field_dev3 = document.getElementById("field_dev_edit3");
    var field_dev_id = document.getElementById("device_id_edit");
    field_dev1.value = dev_code;
    field_dev2.value = dev_name;
    field_dev_id.value = dev_id;

    var type_gate_list = form_edit_dev.type_gate.options;
    for (var i=0; i < type_gate_list.length; i++){
        if (dev_path_img.indexOf(type_gate_list[i].value) !== -1){
            field_dev3.value = type_gate_list[i].value;
            console.log(type_gate_list[i].value);
            break;
        }
    }
    $("#ModalEditDevice").modal('show');
}

function delDevice(dev_id, dev_name){
    console.log("Delete")
    let del_dev = confirm(_("Удалить устройство \"%(d_name)s\" ?", {d_name: dev_name}));
    return del_dev;
}

$(document).ready(function() {
    checkInvalid();

    function checkInvalid(){
        var modalWindowAdd = document.querySelector("#ModalAddDevice");
        var modalWindowEdit = document.querySelector("#ModalEditDevice");
        var elementsListAdd = modalWindowAdd.querySelectorAll(".invalid");
        var elementsListEdit = modalWindowEdit.querySelectorAll(".invalid");
        if (elementsListAdd.length !== 0){
            $("#ModalAddDevice").modal('show');
        }
        if (elementsListEdit.length !== 0){
            $("#ModalEditDevice").modal('show');
        }
    }

    field_dev_add1.oninput = function () {
        if (this.value.length > 8) {
            this.value = this.value.slice(0,8); 
        }
    };

    field_dev_edit1.oninput = function () {
        if (this.value.length > 8) {
            this.value = this.value.slice(0,8); 
        }
    };
    
    var socket = io.connect('http://' + document.domain + ':' + location.port);
    $('#button_add_device').click(function(event) {
        $("#ModalAddDevice").modal('show');
        console.log("Add");
    });
});

Пробовал все методы из поста https://stackoverflow.com/questions/27396248/uwsgi-nginx-flask-upstream-prematurely-closed Не помогло

В чём может быть ошибка: в настройках nginx или в самом коде JS ? Спасибо