Thanks, the error remains, “unknown page” using /posts.rss on one of my site and no error on the two others.
Is the site where it doesn’t work private?
No, I sent a PM to you.
Sorry the error message is “this page is private” when using /posts.rss
With @Moin help, I found this does not work on Firefox only, most probably an issue with my Firefox extensions…
more: works in a private Firefox windows, does not in a normal window, whatever the extensions activated.