Here are few possible causes and solutions to the problem:

1. The site is hosted on is different from self-hosted sites configuration, for example, the files and folders structure. And our plugin is developed based on the platform and currently does not(yet) support

2. The site is on a Nginx server

If your web server is Nginx, please follow this guide to add specific rules to Nginx conf. file to make the staging site to work properly.

3. Cache, redirect or security plugins settings

It is recommended to temporarily deactivate(once the staging site is created, you can re-activate them) all cache, redirect and security plugins on the live site then create a new staging site.