diff --git a/chain_service/controllers/chain.py b/chain_service/controllers/chain.py
index a415206..f251e07 100644
--- a/chain_service/controllers/chain.py
+++ b/chain_service/controllers/chain.py
@@ -38,13 +38,20 @@ async def chain_upsert_controller(
 
 @router.get("/list")
 async def chain_list_controller(
-    namespace_id: str, chain_repository: ChainRepositoryDependency
+    namespace_id: str,
+    chain_repository: ChainRepositoryDependency,
+    namespace_repository: NamespaceRepositoryDependency,
 ):
 
     try:
+        assert await namespace_repository.get_by_id(namespace_id=namespace_id)
         chains = await chain_repository.get_list(namespace_id=namespace_id)
         return chains
 
+    except AssertionError:
+        logger.exception(f"Unknown namespace_id {namespace_id}")
+        return HTTPException(status_code=400, detail="Wrong namespace_id")
+
     except Exception:
         logger.exception("Error during chain list")
         return HTTPException(status_code=500, detail="Error during chain list")