sock error

[birimblongas]

Hi, i have a rails app using unicorn + nginx.
Last month my app started to get really slow and giving me error 502.
Unicorn log doesn't show nothing, either my rails app log.
But looking at nginx error log, i get numerous: 

 [error] 1837#0: *263157 connect() to unix:/tmp/.app.sock failed (11:
Resource temporarily unavailable) while connecting to upstream,


What could it be? What causes this?

If I change from socket to tcp connection, my tcp connection doesn't give
this error, but gets time out.

Thanks for any help.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,259199,259199#msg-259199