diff --git a/docs/features/services/mumble-docker.md b/docs/features/services/mumble-docker.md
index 5b9df018..36fa52b3 100644
--- a/docs/features/services/mumble-docker.md
+++ b/docs/features/services/mumble-docker.md
@@ -67,7 +67,7 @@ Add the following to your `docker-compose.yml` under the `services:` section
         max-file: "5"
 
   mumble-authenticator:
-    build
+    build:
       context: .
       dockerfile: ./mumble-authenticator/Dockerfile
     restart: always