diff --git a/api/services/file_service.py b/api/services/file_service.py
index 6193a3966..521a66604 100644
--- a/api/services/file_service.py
+++ b/api/services/file_service.py
@@ -35,7 +35,7 @@ class FileService:
         filename = file.filename
         if not filename:
             raise FileNotExistsError
-        extension = filename.split(".")[-1]
+        extension = filename.split(".")[-1].lower()
         if len(filename) > 200:
             filename = filename.split(".")[0][:200] + "." + extension