Update docs/user/user-defined-redirects.rst

Co-authored-by: Eric Holscher <[email protected]>

docs/user/user-defined-redirects.rst

@@ -23,7 +23,8 @@ Features
 
 - By default, redirects are followed only if the requested page doesn't exist
   (*404 File Not Found* error), if you need to apply a redirect for files that exist,
-  mark the :guilabel:`Force redirect` option.
+  mark the :guilabel:`Force redirect` option. **This option is only available on some plan levels**.
+  Please ask support if you need it for some reason. 
 - :ref:`user-defined-redirects:page redirects` and :ref:`user-defined-redirects:exact redirects`
   can redirect to URLs outside Read the Docs,
   just include the protocol in ``To URL``, e.g ``https://example.com``.