cURL error 28

I have been using your plugin for Oauth authentication to access JSON from a mobile app. However, I have noticed since activation that I can no longer make PHP changes through the WP Editor and when I traced this back via the ‘Health Check & Troubleshooting’ plugin, I received a cURL 28 error because the loopback check was timing out.
Disabling your plugin prevented this issue from happening again. Could you please tell me how to fix it?