For FiboFilters to work properly, it needs to fetch descriptors from this file:
/wp-content/uploads/fibofilters/filters-descriptors-{$indext_build_id}.json
This process is only performed once, after which the data is stored in the browser cache. For more information on the process please visit our post about In-Browser filtering.
However, if the mentioned JSON file is hosted and served via a CDN, FiboFilters may fail to fetch these descriptors due to a CORS (Cross-Origin Resource Sharing) error. As a result, filters won’t be displayed on your page.
Solution
The solution is to not serve the JSON file and the descriptors via a CDN. As mentioned, the file is fetched only once and then stored in the browser cache, so hosting it on CDN won’t impact your page optimization.
To exclude the file, you need to find a field responsible for URL exclusions in your CDN settings. Such options should be available in every plugin offering CDN services.
Add the following two lines as CDN exclusions in your CDN settings:
fibofilters/filters-descriptors fibofilters\/filters-descriptors