Pidfile exists, but process is dead

I'm trying to run my app.js file but when I do a node app.js status it sais:

Pidfile exists, but process is dead.

I have tried re-starting the app.js file but still causing the problem. When I do node app.js start is sais it started. And when I do node app.js stop is sais it stopped.

But after starting the script and doing node app.js status is sais Pidfile exists, but process is dead.

I know its not an issue with my code as the same code works fine on another server.

Anyone know whats going on?