Indeed, if I remove the personalization of the administration URL, it works. But that removes the point of using this plugin.
For the JSON, I did a test, but that didn’t solve anything.
My site is hosted by Planet Hoster, but I doubt I can touch the firewall on the server side.
I see the 403 error only when i click on the update button (to save the modification) in editor page, not on the options page of the plugin.
And i use the free version of the plugin.
