Issues connecting to the API

I’m building a slideshow thingy for Philomena-based boorus, and Ponybooru is giving me issues:
 
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://ponybooru.org/api/v1/json/search/images?q=safe&page=1&per_page=50&sd=desc&sf=id. (Reason: CORS request did not succeed). Status code: (null).
 
Failed to load ‘https://ponybooru.org/api/v1/json/search/images?q=safe&page=1&per_page=50&sd=desc&sf=id’. A ServiceWorker passed a promise to FetchEvent.respondWith() that rejected with ‘TypeError: NetworkError when attempting to fetch resource.’.
 
The exact same request, but for derpibooru.org works perfectly fine, meanwhile.