samlify: Error on the server side : Cannot read property 'SAMLResponse' of undefined

Hey there ! I am trying to sort my onelogin sso authentification following this example : https://samlify.js.org/#/onelogin

I’m a bit confused by this bit :

router.get('/spinitsso-redirect', (req, res) => {
    const url = sp.createLoginRequest(idp, 'redirect');
    return res.redirect(url);
});

The “url” returned is actually an object ? I had to do url.context to get the url back

I am now trying to access myurl/sso/spinitsso-redirect but getting the following error : TypeError: Cannot read property 'SAMLResponse' of undefined

Any ideas why ? Am I missing something ?