# Unknown TLS options when trying to start container. Really confused why

**URL:** <https://community.traefik.io/t/unknown-tls-options-when-trying-to-start-container-really-confused-why/23211>\
**Category:** Traefik v3 (latest)\
**Tags:** docker\
**Created:** [June 17, 2024, 5:35pm UTC](https://community.traefik.io/t/unknown-tls-options-when-trying-to-start-container-really-confused-why/23211 "2024-06-17T17:35:36Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![kevdog](https://sea2.discourse-cdn.com/flex020/user_avatar/community.traefik.io/kevdog/32/2825_2.png) [@kevdog](https://community.traefik.io/u/kevdog)\
**Post date:** [June 17, 2024, 5:35pm UTC](https://community.traefik.io/t/unknown-tls-options-when-trying-to-start-container-really-confused-why/23211/1 "2024-06-17T17:35:36Z")

</div>

I'm using Traefik version 3 in combination with docker.

My docker file has the following (snippet):

```auto
      - "traefik.http.routers.dashboard.tls=true"
      - "traefik.http.routers.dashboard.tls.options=modern@file"
      - "traefik.http.routers.dashboard.tls.certresolver=le"

```

My dynamic configuration file has the following:

```auto
tls:
  options:
    default:
      minVersion: VersionTLS12
      sniStrict: true
      cipherSuites:
        - TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
        - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
        - TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305
        - TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305
    intermediate: &intermediate_tls
      minVersion: VersionTLS12
      sniStrict: true
      cipherSuites:
        - TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
        - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
        - TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        - TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305
        - TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305
    modern: &modern_tls
      minVersion: VersionTLS13
      cipherSuites:
        - TLS_AES_256_GCM_SHA384
        - TLS_CHACHA20_POLY1305_SHA256
      curvePreferences:
        - CurveP521
        - CurveP384
      sniStrict: true

```

I'm getting the following error however when starting traefik when trying to adjust TLS options:

`2024-06-17T10:18:53-05:00 ERR github.com/traefik/traefik/v3/pkg/server/router/tcp/manager.go:191 > error="unknown TLS options: modern@file" entryPointName=websecure routerName=portainer@docker`

Is there a way to fix this error? Why is modern@file unknown?

---

<div class="post-metadata">

**Author:** ![bluepuma77](https://avatars.discourse-cdn.com/v4/letter/b/a9adbd/32.png) [@bluepuma77](https://community.traefik.io/u/bluepuma77)\
**Post date:** [June 18, 2024, 6:22pm UTC](https://community.traefik.io/t/unknown-tls-options-when-trying-to-start-container-really-confused-why/23211/2 "2024-06-18T18:22:56Z")

</div>

Do you load the dynamic config file via `providers.file` in static config?

What is `&modern_tls`?