How to fix Traefik Dashboard/API 404 page not found "api is not enabled"

Problem:

You are trying to configure the Traefik API/Dashboard in a secure way, but every time you try to access the API, you’re only getting a 404 error (unless you set api.insecure=true)

In the logs, you see an error message like this: (if log.level = "DEBUG"):

traefik    | time="2020-09-20T22:53:51Z" level=error msg="api is not enabled" routerName=my-api@file entryPointName=websecure

Solution

You have to pass --api=true to Traefik, e.g. using docker-compose:

command:
  - "--api=true"

and also set

[api]
dashboard = true

in your traefik.toml.

After that, restart Traefik and you should be able to access your dashboard at /dashboard.

Credits to multiple GitHub users for the original solution.