Puppeteer / POST Request

I’m trying now since over 48 hours and googelt almost the whole web. My problem is that when use puppeteer the POST Request is not working – I tried many websites but the POST Form Action is not working. Can somebody help me?

File test.js
Usage: node test.js

const puppeteer = require('puppeteer');
const randomUseragent = require('random-useragent');
const USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.75 Safari/537.36';

(async () => { const browser = await puppeteer.launch({ args: ['--no-sandbox'] }) // headless: true,

const page = await browser.newPage()
    
await page.setViewport({
    width: 1920 + Math.floor(Math.random() * 100),
    height: 3000 + Math.floor(Math.random() * 100),
    deviceScaleFactor: 1,
    hasTouch: false,
    isLandscape: false,
    isMobile: false,
});

const userAgent = randomUseragent.getRandom();
const UA = userAgent || USER_AGENT;

await page.setUserAgent(UA);
await page.setJavaScriptEnabled(true);
await page.setDefaultNavigationTimeout(0);

await page.setRequestInterception(true);
page.on("request", interceptedRequest => {

        var data = {
            
            "method": "POST",
            "postData": "URLz=VIDEOURL"
        };
        interceptedRequest.continue(data);
    });
    
const response = await page.goto('https://fdown.net/download.php')
 //const responseBody = await response.text();
 
await page.screenshot({ path: 'affe.png', fullPage: true })
await browser.close()

})()