MERN App - Error when hosting my app on heroku - node.js

Question

different response result when I use localhost url or the heroku url
As you can see in the picture, in blue we succesfully have the result response. But not when hosted in heroku (green on picture).
Here is the response from api when I try to fetch:
response
But those params are set in .env file (backend).
Can someone help me with this ? The cors is configured on the backend, so I don't know what I can do more...
server.js:
const express = require("express");
const path = require("path");
const bodyParser = require("body-parser");
const cors = require("cors");
const dotenv = require("dotenv");
const colors = require("colors");
const dbConnect = require("./database/dbConnect");
dotenv.config();
// *** ROUTES IMPORT ***
const usersRoutes = require("./routes/users-routes");
const ovhRoutes = require("./routes/ovh-routes");
const renewDomainsRoutes = require("./routes/renew-domain-routes");
const meRoutes = require("./routes/me-routes");
const internetBsRoutes = require("./routes/internetbs-routes");
const domainsRoutes = require("./routes/domains-routes");
const orderRoutes = require("./routes/order-routes");
// execute database connection
dbConnect();
const app = express();
app.use(bodyParser.json());
app.use(cors());
/**
* ROUTES
*/
app.use("/api/users", usersRoutes); // => /api/users/...
app.use("/api/ovh", ovhRoutes); // => /api/ovh/...
app.use("/api/renew", renewDomainsRoutes);
app.use("/api/me", meRoutes);
app.use("/api/internetbs", internetBsRoutes);
app.use("/api/domains", domainsRoutes);
app.use("/api/order", orderRoutes);
app.use((req, res, next) => {
throw new HttpError("Could not find this route.", 404);
});
app.use((error, req, res, next) => {
if (res.headerSent) {
return next(error);
}
res.status(error.code || 500);
res.json({ message: error.message || "An unknown error occurred!" });
});
/**
* DEPLOYMENT
*/
if (process.env.NODE_ENV === "production") {
// Step 1:
app.use(express.static(path.resolve(__dirname, "./client/build")));
// Step 2:
app.get("*", function (request, response) {
response.sendFile(path.resolve(__dirname, "./client/build", "index.html"));
});
}
app.listen(
process.env.PORT || 5000,
console.log(`Server is running on port ${process.env.PORT}`.blue.bold)
);
The data are fetched from internet.bs API.
Thanks all!