diff --git a/backend/server.py b/backend/server.py
index 62d6b48..38746bf 100644
--- a/backend/server.py
+++ b/backend/server.py
@@ -1534,7 +1534,8 @@ async def stream_track(
     if not file_path.is_file(): raise HTTPException(status_code=404, detail="File missing on disk")
 
     file_size = file_path.stat().st_size
-    content_type = mimetypes.guess_type(str(file_path))[0] or "audio/mpeg"
+    _audio_mime_fallback = {".m4a": "audio/mp4", ".flac": "audio/flac", ".ogg": "audio/ogg", ".wav": "audio/wav", ".aac": "audio/aac"}
+    content_type = mimetypes.guess_type(str(file_path))[0] or _audio_mime_fallback.get(file_path.suffix.lower(), "audio/mpeg")
     range_header = request.headers.get("range") or request.headers.get("Range")
     if range_header and range_header.startswith("bytes="):
         try: