diff --git a/.env.example b/.env.example
index ec7ab201..7e29b8e5 100644
--- a/.env.example
+++ b/.env.example
@@ -80,8 +80,10 @@ CACHE_TRANSCODE_MINUTES=60
 SUBSONIC_URL=http://localhost:4533
 
 # ===== JELLYFIN CONFIGURATION =====
-# Server URL (required if using Jellyfin backend)
-JELLYFIN_URL=http://localhost:8096
+# Server URL (required if using Jellyfin backend).
+# From Docker, localhost is the Allstarr container. Use host.docker.internal for
+# Jellyfin on the Docker host, or the Jellyfin service name on a shared network.
+JELLYFIN_URL=http://host.docker.internal:8096
 
 # API key for SERVER-SIDE operations only (get from Jellyfin Dashboard > API Keys)
 # This is used by Allstarr to query Jellyfin's library on behalf of the server
diff --git a/README.md b/README.md
index 55c82ab7..53a40570 100644
--- a/README.md
+++ b/README.md
@@ -200,8 +200,8 @@ Choose your preferred provider via the `MUSIC_SERVICE` environment variable. Add
    # Backend selection
    BACKEND_TYPE=Jellyfin
 
-   # Jellyfin server URL
-   JELLYFIN_URL=http://localhost:8096
+   # Jellyfin on the Docker host (use its service name on a shared Docker network)
+   JELLYFIN_URL=http://host.docker.internal:8096
 
    # API key (get from Jellyfin Dashboard > API Keys)
    JELLYFIN_API_KEY=your-api-key-here
@@ -213,6 +213,10 @@ Choose your preferred provider via the `MUSIC_SERVICE` environment variable. Add
    JELLYFIN_LIBRARY_ID=
    ```
 
+   `localhost` inside the Allstarr container points to Allstarr itself, not to
+   Jellyfin. The Compose file maps `host.docker.internal` on Linux, macOS, and
+   Windows for a Jellyfin server running on the Docker host.
+
    ```bash
    # Path where downloaded songs will be stored
    DOWNLOAD_PATH=./downloads
diff --git a/allstarr.Tests/AdminAuthControllerTests.cs b/allstarr.Tests/AdminAuthControllerTests.cs
index 233b3393..27a1abee 100644
--- a/allstarr.Tests/AdminAuthControllerTests.cs
+++ b/allstarr.Tests/AdminAuthControllerTests.cs
@@ -63,7 +63,9 @@ public class AdminAuthControllerTests
         Assert.NotNull(capturedRequest);
         Assert.Equal(HttpMethod.Post, capturedRequest!.Method);
         Assert.Equal("http://jellyfin.local/Users/AuthenticateByName", capturedRequest.RequestUri?.ToString());
-        Assert.Contains("X-Emby-Authorization", capturedRequest.Headers.Select(h => h.Key));
+        Assert.StartsWith("MediaBrowser Client=\"AllstarrAdmin\"",
+            capturedRequest.Headers.GetValues("Authorization").Single());
+        Assert.False(capturedRequest.Headers.Contains("X-Emby-Authorization"));
 
         Assert.NotNull(capturedBody);
         Assert.Contains("\"Username\":\"josh\"", capturedBody!);
diff --git a/allstarr/AppVersion.cs b/allstarr/AppVersion.cs
index 477b2304..206d9ae5 100644
--- a/allstarr/AppVersion.cs
+++ b/allstarr/AppVersion.cs
@@ -9,5 +9,5 @@ public static class AppVersion
     /// <summary>
     /// Current application version.
     /// </summary>
-    public const string Version = "2.0.2";
+    public const string Version = "2.0.3";
 }
diff --git a/allstarr/Controllers/AdminAuthController.cs b/allstarr/Controllers/AdminAuthController.cs
index 39363801..5a8a4d2e 100644
--- a/allstarr/Controllers/AdminAuthController.cs
+++ b/allstarr/Controllers/AdminAuthController.cs
@@ -64,7 +64,7 @@ public class AdminAuthController : ControllerBase
             {
                 Content = new StringContent(loginJson, Encoding.UTF8, "application/json")
             };
-            httpRequest.Headers.TryAddWithoutValidation("X-Emby-Authorization", authHeader);
+            httpRequest.Headers.TryAddWithoutValidation("Authorization", authHeader);
 
             using var response = await _httpClient.SendAsync(httpRequest);
 
diff --git a/docker-compose.yml b/docker-compose.yml
index fe83c7e1..68df1d7c 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -66,6 +66,9 @@ services:
       start_period: 40s
     networks:
       - allstarr-network
+    extra_hosts:
+      # Lets Linux containers reach Jellyfin running on the Docker host.
+      - "host.docker.internal:host-gateway"
     environment:
       - ASPNETCORE_ENVIRONMENT=Production
       # Backend type: Subsonic or Jellyfin (default: Subsonic)
@@ -101,7 +104,7 @@ services:
       - Subsonic__PlaylistsDirectory=${PLAYLISTS_DIRECTORY:-playlists}
 
       # ===== JELLYFIN BACKEND =====
-      - Jellyfin__Url=${JELLYFIN_URL:-http://localhost:8096}
+      - Jellyfin__Url=${JELLYFIN_URL:-http://host.docker.internal:8096}
       - Jellyfin__ApiKey=${JELLYFIN_API_KEY:-}
       - Jellyfin__UserId=${JELLYFIN_USER_ID:-}
       - Jellyfin__LibraryId=${JELLYFIN_LIBRARY_ID:-}