Steps to reproduce:
- Go to any file page on Commons.
- Select "Edit source" and change something.
Shows no preview content, only error message:
Error loading data from server: Error contacting the Parsoid/RESTBase server (HTTP 403).
I tried reproducing this on a subpage to my user page, but that gave no error, even with the same content from the file page. Maybe it's dependent on the namespace somehow?
Browser: Firefox 70.0.1 (64-bit).