6ruff

Fixed!
It was a problem in the lighttpd config – the docroot in the fastcgi config was incorrect.
Strange how the majority of WordPress worked and that only ajax requests were affected by this issue.

After looking into this a bit more I can see that the 404 responses are being returned for multiple ajax actions posted to admin-ajax.php, for example actions “theme-install” and “heartbeat”.

The actions all seem to return valid response bodies, but a 404 status.
For example the response body for “theme-install” starts with:

{“success”:true,”data”:{“info”:{“page”:1,”pages”:1,”results”:15},”themes”:[{“name”:”…..

Same error appears with Chrome and Safari browser.

I also have this error in 4.5.3. The URL /wp-admin/admin-ajax.php is returning a 404 in the admin screens, for example in Appearance->Themes->Add New->Featured.

I have checked file permissions and that the file is actually present and I get the following response:

Date: Wed, 13 Jul 2016 21:22:59 GMT
Server: lighttpd/1.4.39
X-Powered-By: PHP/7.0.7
Transfer-Encoding: chunked
Content-type: text/html; charset=UTF-8

404 Not Found

I did have to set define(‘CONCATENATE_SCRIPTS’, false); in wp-config to fix another issue, so I wonder if this is related (removing CONCATENATE_SCRIPTS makes the admin screens practically unusable).

I’m *very* new to WP so any help gratefully received!