routes/index.js

const allRoutes = express()

allRoutes.get("/", async (req, res, next) => {
    return res.status(200).json({
        title: "Express Testing",
        message: "The app is working properly!",
    })
})

allRoutes.use("/auth", authRoutes)
allRoutes.use("/user", userRoutes)
allRoutes.use("/product", productRoutes)
allRoutes.use("/order", orderRoutes)

export default allRoutes

api/index.js

import allRoutes from "../routes/index.js"

app.use("/api/v1", allRoutes) 

After trying to deploy MERN app to vercel, the backend route only can run allRoutes.get("/") and other routes showed that This Serverless Function has timed out.. I could not figure out why will the function has timed out but vercel is working properly so I would like to look for a suggested solution to fix the problem

I followed the deployment guide step by step in Vercel documentation but still had error occurred at last