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.