Getting the "index of/" page when accessing my website using my domain (DNS) but the real site when using the IP directly

Im hosting my website on a DigitalOcean droplet. I use the DigitalOcean DNS service to point my domain name to the droplet.

When accessing the website directly using the IP i get my website (a python Flask app) but when accessing it using the domain name I get the "index of/" pages which then displays all the files etc.

Do anyone have any suggestion how to fix this such that the domain name returns a rendered web instead of the directory?

Best regards