Cannot negotiate ALPN protocol (Docker environment)

Just the following:

traefik_1 | time="2020-12-06T20:37:23Z" level=info msg="Configuration loaded from flags."

This being said, my acme.json is still empty (I used chmod 600 on it just fyi). I added it inside my docker-compose but it doesn't appear inside the traefik container's root. Not sure if it's normal..