Application shows the error: Element type is invalid when in StrickMode

[francisrod01]

Application shows the error: Element type is invalid when in StrickMode

• "react": "16.3.2",
• "react-bootstrap-sweetalert": "^4.1.0",
• "react-burger-menu": "^2.5.2",
• "react-datetime": "2.11.0",
• "react-dom": "16.1.0",
• "react-frontload": "^1.0.3",
• "react-google-maps": "9.2.2",
• "react-helmet": "^5.2.0",
• "redux": "^3.7.2",
• "redux-actions": "^2.3.0",
• "redux-persist": "^5.9.1",
• "redux-saga": "^0.16.0",
• "react-redux": "^5.0.7",
• "react-responsive-modal": "^3.0.3",
• "react-router": "^4.2.0",
• "react-router-dom": "4.2.2",
• "react-router-redux": "5.0.0-alpha.9",

const { store, persistor } = configureStore();
//console.log(persistor);
//persistor.purge();
const history = store.getHistory();

registerAxiosInterceptors();

const Application = (
    <ReduxProvider store={store}>
        <PersistGate loading={null} persistor={persistor}>
            <Router history={history}>
                <Frontload noServerRender={true}>
                    <ThemeZero />
                </Frontload>
            </Router>
        </PersistGate>
    </ReduxProvider>
);

const root = document.querySelector('#root');

if (root.hasChildNodes() === true) {
    // If it's an SSR, we use hydrate to get fast page loads by just
    // attaching event listeners after the initial render.
    Loadable.preloadReady().then(() => {
      hydrate(Application, root);
    });
}
else {
    // If we're not running on the server, just render like normal
    render(Application, root);
}

Uncaught Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: symbol.
    at invariant (invariant.js:42)
    at createFiberFromElement (react-dom.development.js:5731)
    at reconcileSingleElement (react-dom.development.js:7532)
    at reconcileChildFibers (react-dom.development.js:7636)
    at reconcileChildrenAtExpirationTime (react-dom.development.js:7768)
    at reconcileChildren (react-dom.development.js:7751)
    at updateHostRoot (react-dom.development.js:7946)
    at beginWork (react-dom.development.js:8235)
    at performUnitOfWork (react-dom.development.js:10215)
    at workLoop (react-dom.development.js:10279)

[cereallarceny]

Can you be more specific @francisrod01 ?