When i fetch Heroku deployed a link, there is an error 500 (Internal Server Error)

Question

If i used http://localhost:5000/login everything is working. When i used live link https://auto-shoroom.herokuapp.com/login there's the error POST https://auto-shoroom.herokuapp.com/login 500 (Internal Server Error)

The code below with live Heroku link .This code aren't working

if (user) {
        fetch('https://auto-shoroom.herokuapp.com/login', {
            method: 'POST',
            body: JSON.stringify({
                email: user.email 
            }),
            headers: {
                'Content-type': 'application/json',
            },
        })
            .then(res => res.json())
            .then(data => {
                localStorage.setItem("accessToken", data.token)
                navigate(from, { replace: true });
            });
    }

The code below with localhost link .This code is working

if (user) {
        fetch('http://localhost:5000/login', {
            method: 'POST',
            body: JSON.stringify({
                email: user.email 
            }),
            headers: {
                'Content-type': 'application/json',
            },
        })
            .then(res => res.json())
            .then(data => {
                localStorage.setItem("accessToken", data?.token)
                navigate(from, { replace: true });
            });
    }

Answer 1

Check Reveal Config Vars in your heroku project setting. And you need to add KEY and VALUE in Reveal Config Vars. And that's key value in your .env file.