405 Error for POST request

const express = require('express');
const app = express();
app.listen(3000, () => console.log('listening at 3000'));
app.use(express.static('public'));
app.use(express.json({ limit: '1mb' }));
app.post('/api', (request, response) => {
    console.log(request.body);
    response.json({ message: 'POST request received' });
});

if ('geolocation' in navigator) {
    console.log('geolocation available');
    navigator.geolocation.getCurrentPosition(position => {
        console.log(position.coords.latitude, position.coords.longitude);
        const lat = position.coords.latitude.toFixed(2);
        const lng = position.coords.longitude.toFixed(2);
        const latDisp = document.getElementById("lat");
        const lngDisp = document.getElementById("lng");
        latDisp.innerText = lat;
        lngDisp.innerText = lng;

        const data = { lat, lng };
        const options = {
            method: 'POST',
            headers: {
                "Content-Type": "application/json",
            },
            body: JSON.stringify(data)
        };
        fetch('/api', options);
    });
} else {
    console.error('geolocation IS NOT avaiable');
}