Error adding new collection

Hi,
Just tried to add a project to a collection but got the follwoign error message:
XMLHttpRequest cannot load https://www.instructables.com/json-api/newGuide. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://www.instructables.com' is therefore not allowed access. The response had HTTP status code 405.