Error while trying to login with through Steam from node.js

Question

I'm trying to login through steam from my webapp but I'm having an hard time.

This is the code in my backend (I'm using Firebase cloud functions) that let me authenticate my user.

const steam = new SteamAuth({
    realm: "https://storm.co.gg", // Site name displayed to users on logon
    returnUrl: "http://localhost:5001/stormtestfordota/europe-west1/api/auth/steam/authenticate", // Your return route
    apiKey: apiKey // Steam API key
});
let loggedUser = "";

const redirectSteamAuth = async (req, res) => {
    loggedUser = req.user.username;
    
    const redirectUrl = await steam.getRedirectUrl();
    return res.json(redirectUrl);
}

So this is the first endpoint that the user calls when trying to login to Steam. And it works, so the steamcommunity.com opens without problem. But when I click login in steamcommunity page I'm prompted with this error

So over the name of my account you can see "ERRORE" that stands for "ERROR"

This is the endpoint that should be called after authentication:

const loginWithSteam = async (req, res) => {
    try {
        const user = await steam.authenticate(req);

        db.collection("users").doc(loggedUser).update({
            steamId: user.steamid
        })

        activeDota2(loggedUser, user.steamid);

        return res.redirect("https://storm.co.gg/dashboard/home");
    } catch (error) {
        console.error(error);
        return res.status(401).json(error)
    }
}

These are the two endpoints:

app.post("/auth/steam", (req, res, next) => validateFirebaseIdToken(req, res, next), redirectSteamAuth);
app.get("/auth/steam/authenticate", loginWithSteam);

Answer 1

I solved this issue. The problem was in the urls of the steam object AND there was a problem with CORS options, I didn't add the DNS of steamcommunity in origins accepted by CORS.