Node.Js and Forever on centos - Sigkill

I'm running a Node.js process on a Centos Server with forever. Whatching the log I've noticed that the application is restarted every 20sec with this message:

error: Forever detected script was killed by signal: SIGKILL

While if I simply run my application with: node index.jsthe app seem to be stable (of course untill I close the ssh connection), so I think that this is not an application issue, but a server configuration problem.

Searching for the error I found this discussion: why node.js process is killed?

but this is not helpfull to me...

Any suggestion on what to check to solve this issue? This is really making me crazy