I made a model target database by Model Target Generator, and test it in Model Target Test App. It works well.

But when I imported it to my unity demo,and run it on Hololens2 , nothing appeard when I focus on the Object.

My Unity version is 2019.4.4 ,Windows SDK 10.0.19041.0, I have Imported the Vuforia plugin: "Vuforia Hololens 1+2 Sample for Unity 2019.4 LTS",and replaced the mode target database in "2-ModelTargets" scene. And I also  have tried create a model target in an empty scene. none of them worked.

Does anybody know what to do about it