diff --git a/tests/remote/unit/test_handlers_serialize.py b/tests/remote/unit/test_handlers_serialize.py
index 57f0f2a2..52c986be 100644
--- a/tests/remote/unit/test_handlers_serialize.py
+++ b/tests/remote/unit/test_handlers_serialize.py
@@ -2,12 +2,16 @@
 
 from __future__ import annotations
 
+import io
+
 import pytest
+import requests
 from langcodes import Language
 
 from unshackle.core.api.errors import APIError, APIErrorCode
 from unshackle.core.api.handlers import (
     drm_preference_name,
+    listed_titles,
     sanitize_log,
     search_handler,
     serialize_audio_track,
@@ -135,6 +139,26 @@ def test_serialize_title_episode_unnamed_falls_back_to_number() -> None:
     assert d["name"] == "Episode 05"
 
 
+def test_no_titles_is_a_service_error() -> None:
+    with pytest.raises(APIError) as exc:
+        listed_titles(None)
+    assert exc.value.error_code == APIErrorCode.SERVICE_ERROR
+
+
+def test_init_segment_reports_the_http_status() -> None:
+    refused = requests.Response()
+    refused.status_code = 403
+    refused.raw = io.BytesIO()
+
+    class FakeSession(requests.Session):
+        def request(self, *args: object, **kwargs: object) -> requests.Response:
+            return refused
+
+    track = Video(url="https://cdn.example/v.mp4", language=Language.get("en"))
+    with pytest.raises(ValueError, match="HTTP 403"):
+        track.get_init_segment(session=FakeSession())
+
+
 def test_serialize_video_track_basic() -> None:
     d = serialize_video_track(video())
     assert d["id"] == "video-001"
diff --git a/unshackle/core/api/handlers.py b/unshackle/core/api/handlers.py
index bfdbac31..05c7fefe 100644
--- a/unshackle/core/api/handlers.py
+++ b/unshackle/core/api/handlers.py
@@ -1077,6 +1077,13 @@ def part_key_suffix(part: Optional[int]) -> str:
     return f".{part}" if part is not None else ""
 
 
+def listed_titles(titles: Any) -> list[Any]:
+    """The result of a service's get_titles() as a list."""
+    if titles is None:
+        raise APIError(APIErrorCode.SERVICE_ERROR, "The service returned no titles.")
+    return list(titles) if hasattr(titles, "__iter__") and not isinstance(titles, str) else [titles]
+
+
 def serialize_title(title: Title_T) -> Dict[str, Any]:
     """Convert a title object to JSON-serializable dict."""
     title_language = str(title.language) if hasattr(title, "language") and title.language else None
@@ -1560,10 +1567,7 @@ async def list_titles_handler(data: Dict[str, Any], request: Optional[web.Reques
         )
         titles = await asyncio.to_thread(service_instance.get_titles)
 
-        if hasattr(titles, "__iter__") and not isinstance(titles, str):
-            title_list = [stamp_service_flags(serialize_title(t), service_instance) for t in titles]
-        else:
-            title_list = [stamp_service_flags(serialize_title(titles), service_instance)]
+        title_list = [stamp_service_flags(serialize_title(t), service_instance) for t in listed_titles(titles)]
 
         return request_cache.json_response({"titles": title_list})
 
@@ -3558,10 +3562,7 @@ async def session_titles_handler(session_id: str, request: Optional[web.Request]
                 session.touch()
         session.titles = titles
 
-        if hasattr(titles, "__iter__") and not isinstance(titles, str):
-            titles_list = list(titles)
-        else:
-            titles_list = [titles]
+        titles_list = listed_titles(titles)
 
         serialized_titles = []
         for t in titles_list:
diff --git a/unshackle/core/tracks/track.py b/unshackle/core/tracks/track.py
index 6aff7909..0c2f7e3b 100644
--- a/unshackle/core/tracks/track.py
+++ b/unshackle/core/tracks/track.py
@@ -1095,6 +1095,9 @@ class Track:
         else:
             init_data = None
             s = session.get(url, stream=True)
+            if not s.ok:
+                s.close()
+                raise ValueError(f"Track URI returned HTTP {s.status_code}")
             for chunk in s.iter_content(content_length):
                 init_data = chunk
                 break