Cesium cant read my glb flie

1. A concise explanation of the problem you’re experiencing.

Cant get Cesium to read my glb file eventhouge I can get it to load in https://www.virtualgis.io/gltfviewer/

2. A minimal code example. If you’ve found a bug, this helps us reproduce and repair it.

The cesium 3d model sand castle example. using this file

I get the error :

“Failed to load model: http://localhost:8080/assets/f15raam.glb

4. The Cesium version you’re using, your operating system and browser.

latest

What version of Cesium are you on? I’m trying it on master and it works (screenshot attached).