I'm facing with this error from few days, maybe weeks. I've tried and tried and tried all kind of solutions over the internet but with no success, so:
I have a dedicated server with Plesk 12 and Ubuntu 14.04 LTS.
This error appear daily, 1-2 times per day and I have to restart whole server and then all websites are working properly until next time this error appear again.
First time it appeared when I have added two more domains to be hosted. I suspected high server loading but no, rams never gets almost completely and cpu load is max 20%.
PS: Error appear only on websites, so I can access Plesk Panel and reboot server.
NGINX error log (/var/log/nginx/error.log):
[error] 1406#0: *119083 connect() failed (111: Connection refused) while connecting to upstream, client: IP, server: , request: "GET http://www.example.com/ HTTP/1.1", upstream: "http://SERVER_IP:7080/", host: "www.example.com"
It is first time when I'm using Plesk and I don't really know how to do or check... .
PS: Can this be caused by a cron job service? Cron log which is worrying me:
254 postfix/master[1664]: warning: master_wakeup_timer_event: service pickup(public/pickup): Connection refused
this error means that something goes wrong with Apache or PHP-FPM(if you have using it), check apache logs of site where it happens: /var/www/vhosts/examples.com/logs/error_log