I've just upgraded to WordPress 5, and all is working fine on the main site.
However on the two sub-branch sites, when I try to create a new post, I receive a white screen and the console reports 404 errors when trying to retrieve the following files:
wp-includes/js/api-request.js?ver=5.0.3 wp-includes/js/dist/api-fetch.js?ver=2.2.7 wp-includes/js/wp-api.js?ver=5.0.3
The files are definitely there, all other files are being retrieved correctly from the same and similar locations.
There are no bugs reported in the debug file, I have reset permalinks and have tried deactivating all plugins.
Does anyone kindly have any suggestions?
If my question isn't welcome, it would be appreciated if it isn't downvoted - Stack Overflow is allegedly trying to become more welcoming - it seems this page hasn't caught on yet.