I just moved my Piwik install to a new server running Nginx, and whenever I try to login I get the following error message:
Error: Form security failed. Please reload the form and check that your cookies are enabled. If you use a proxy server, you must configure Piwik to accept the proxy header that forwards the Host header. Also, check that your Referrer header is sent correctly.
I’ve googled, and the referrer is definitely being passed correctly (at least it is for other sites on the same server with practically the same config). Any ideas?