WordPress Rest API 401 response / 403 forbidden when saving pages

Hi,

I have RankMath free setup on a multisite install with multiple domains / subdomains.

RankMath is active on 2 of the domains, working fine on the primary domain.

On the secondary domain where it is active neither the dashboard widget or saving pages works.

The WP Rest API endpoints for that site are reachable but appears to have missing routes.

The domains are behind CloudFlare which had rules in place to disable security for both domains.

There are no active security / caching plugins and the CF / browser cache / cookies have been cleared and I am using the same admin account.

There is nothing in error_log that seems relevant and I have permalinks setup the same for both domains.

I’m not sure what else to check, the plugin is not network active but activated individually per domain.

Any help with this would be appreciated.