Rather than allowing Traefik to use the container name for the app's subdomain, you may want to manually choose the domain/subdomain used. Adding this additional label, you are able to manually override the default docker provider rule.
If you are using docker-compose then you simply need to add a single line to the compose files under labels:
WARNING
You must replace app with the name of your application that this label is being added to otherwise Traefik will see duplicates.
To show you a full example, we will add the label to an existing docker-compose.yml file for Adminer.
Now while in the same directory as the docker-compose.yml file, run the command docker-compose up -d and it should recreate the container for you with the latest labels. Now, when you deploy your application, you will be able to visit it by going to your domain with the app name as the subdomain (APP-NAME.DOMAIN.COM).
PLEASE NOTE
You can add multiple of these labels at once before finally deploying your application.
Traefik will now use your preferred subdomain to forward all traffic on to the app correctly.