diff --git a/tg_ws_proxy.py b/tg_ws_proxy.py
index 3fdd435..d5da6ba 100644
--- a/tg_ws_proxy.py
+++ b/tg_ws_proxy.py
@@ -39,7 +39,7 @@ _dc_opt: Dict[int, Optional[str]] = {}
 # DCs where WS is known to fail (302 redirect)
 # Raw TCP fallback will be used instead
 # Keyed by (dc, is_media)
-_ws_blacklist: Set[Tuple[int, bool]] = {}
+_ws_blacklist: Set[Tuple[int, bool]] = set()
 
 # Rate-limit re-attempts per (dc, is_media)
 _dc_fail_until: Dict[Tuple[int, bool], float] = {}