Problems using Testcafe for mobile testing (e. g. testcafe remote tests/test.js --qr-code)

I have problems running my tests on my mobile phone. I am using the instructionsfrom the website: https://ift.tt/3ea6kPS. But unfortunately my iPhone only opens the browser and nothing happens after I scanned the QR code. I connected my iPhone via Hotspot from my laptop on which testcafe is running. Am I am doing something wrong with setting up the network for my test? On the Testcafé website it says: "Scan the QR-code with a mobile device that has network access to the TestCafe machine and open the link."

Any ideas what I am doing wrong?