Protractor - invalid SSL certificate

This works for me, (in conf file):

capabilities: {
    browserName : 'firefox',
    marionette : true,
    acceptInsecureCerts : true
}

Hope that helps.

capabilities: {
    browserName: 'chrome',
    chromeOptions: {
        // for ci test
        args: ['--headless', 'no-sandbox', "--disable-browser-side-navigation",
            "--allow-insecure-localhost"
            /// for https sites: ignore ssl on https://localhost...
            /// further args please see https://peter.sh/experiments/chromium-command-line-switches/
        ]
    }
}

maybe you want to take some screenshots to test where the error occurs

import fs from 'fs';

function writeScreenShot(data, filename) {
    const stream = fs.createWriteStream(filename);
    stream.write(new Buffer(data, 'base64'));
    stream.end();
}

export function takeScreenshot(browser, path){
    browser.takeScreenshot().then((png) => {
        writeScreenShot(png, path);
    });
}

But for the long run, I would suggest migrating to cypress (https://www.cypress.io/), because it have many other features out of the box: video, screenshot, etc. And believe me, it is worth it ;)