diff --git a/toargridding/toar_rest_client.py b/toargridding/toar_rest_client.py
index 607dd0f7894d2df505407169e5bfe2f8f40023c1..fec25bc0be9f8a97a3c17fbd00534bee28c43720 100644
--- a/toargridding/toar_rest_client.py
+++ b/toargridding/toar_rest_client.py
@@ -111,7 +111,7 @@ class Cache:
         
         if not cache_dir.exists():
             raise RuntimeError(f"Given directory for saving cache file does not exists. Path: {cache_dir}")
-        self.cache_file = cache_dir / fn / ".json"
+        self.cache_file = cache_dir / f"{fn}.json"
 
         if not self.cache_file.is_file():  # initialize cache with dummy values
             with open(self.cache_file, "w") as cache: