Got something strange in nginx logs for all webmails:
2014/10/09 14:16:07 [warn] 6062#0: *3050685 using uninitialized "var_domain" variable, client: 89.73.68.10, server: webmail.xxx.com.pl, request: "POST /?/Ajax/ HTTP/1.1", host: "webmail.webmama.com.pl", referrer: "http://webmail.xxx.com.pl/"