Device tracker not working

Hi friends!

I was using extend tracking with a job I was doing.

It´s a shale, thats apear when the camera finds the target and then, it stays there for a while.

But now, I have update the vuforia and I saw that "extend tracking" is dreprecated and now we have "device tracker".

I check this option and set the configuration to "positional" and the "optimize" to image targets.

But now, when the camera finds the target, the whale apears but when the camera move a little from the target, it hides.

Are the any other configurations that I have to do?

Thanks!