Cannot get cors to work for the life of me

This is my first time using cors and node.js, I am trying to call a Web API hosted on one URL from another URL.

I cannot even get cors to work simple app.use(cors());

I tried more complex configurations with origins and whatnot, still no luck.

The api lives on https://api.example.app and is being called from https://myapp.example.app

I am getting all kinds of cors errors.

Note, I am also using CloudFlare and Nginx Proxy Manager

Also, I CAN go to the https://api.example.app/select and get back my data that way without issue. But thats the only scenario working.

var express = require('express');
var mysql = require('mysql');
var cors = require('cors');
var app = express();
var port = 3333;

app.use(express.text());

app.use(cors());

var pool = mysql.createPool({
    connectionLimit: 10,
    host: '192.168.1.200',
    port: 3306,
    user: 'user',
    password: 'password',
    database: 'mydb'
});

app.get('/select', (req, res) => {
    pool.query('SELECT * FROM mytable', (error, results, fields) => {
        if (error) {
            console.error('Error retrieving data:', error);
            return res.status(500).send('Failed to retrieve data from database');
        }
        console.log('Data retrieved successfully:', results);
        res.status(200).json(results);
    });
});

app.post('/insert', (req, res) => {
    var string = req.body;

    console.log(req.body);

    if (!string) {
        return res.status(400).send('String is required');
    }

    pool.query('INSERT INTO mytable(user) VALUES (?)', string, (err, results) => {
        if (err) {
            console.error('Error inserting string into database:', err);
            return res.status(500).send('Failed to insert string into database');
        }

        console.log('String inserted successfully');
        return res.status(200).send('String inserted successfully');
    });
});

app.listen(port, () => {
    console.log(`Server is running on http://192.168.1.200:${port}`);
});

Errors with the current config above.

I think I have it back to working with a combination of Cloudflare configs, but unfortunately, I am not confident in which settings are helping or not helping. All I know is that it works. So I don't really want to post an answer unless I can just say this, but I do want to close the issue...

Cloudflare settings seem to take a little while to not be in affect from my testing where it would work one day after changing a setting but not the next. Maybe a caching thing.

If someone wants to look at my CF config on a discord screenshare to help determine what should be setup or not. I would still be open to that to help come to a clear conclusion. Otherwise, its dust in the wind.

Thanks everyone.