Welcome to the community @vincentsteiner!
This is actually a common situation that occurs during the DNS propagation process but normally it resolves itself and requires no additional steps on your part. This is why DNS changes mention taking 24-48 hours to complete.
If you visited the site before the propagation was finished it may persist a bit longer on your machine due to caching, however I just checked your URL and am taken to the correct site with only the single “www”:
If you’re still experiencing an issue on your end, please try visiting the website in an incognito window and/or clearing your browser’s cache manually as that typically solves the problem 