Nintex Newbie

Nintex Taskform - The remote server returned an error: (404) Not Found.

I have created a nintex workflow for assigning a task.I am using nintex task form for the same.When i try to view/Edit task i am getting a error message 404 not found with correlation ID.I am facing this issue in specific site collection.I have created new task list and tried publishing the workflow but i got same error.