Task's Failed state

Good afternoon !, so I'm using REST API to execute a task using external URL FORM, when I send the post method to execute the task, it gives me 204 Response from the server and everything seems to be working fine, but when I look back in the portal, I find out that the state of that task is FAILED !  What can trigger task failure ?  NB: Im using bonita 7.10.4 Community version 

Did you check your server logs ? Failed tasks often means exceptions server side ( possible issues in connector/script execution)