Getting error when trying to create an asset

Loading this page…
http://wordpress-464864-1737226.cloudwaysapps.com/cesium/checkmap.php

An error occurred while rendering. Rendering has stopped.
RuntimeError: Program failed to link. Link log: ERROR: Implementation limit of 16 MAX_VERTEX_ATTRIBS (e.g., number of generic plus conventional active vec4 attributes) exceeded, shader uses up to vec4 attribute 499.

Error
at new RuntimeError (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:1:42250)
at createAndLinkProgram (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:374244)
at reinitialize (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:376202)
at initialize$g (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:376134)
at ShaderProgram._bind (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:379974)
at beginDraw (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:2230489)
at Context.draw (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:2232042)
at DrawCommand.execute (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:337169)
at executeCommand (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:2937508)
at executeCommands (https://cesium.com/downloads/cesiumjs/releases/1.88/Build/Cesium/Cesium.js:50:2943409)

<body>

  <div id="cesiumContainer">

  <script>
// Grant CesiumJS access to your ion assets
Cesium.Ion.defaultAccessToken = 
var viewer = new Cesium.Viewer("cesiumContainer", {
  terrainProvider: new Cesium.CesiumTerrainProvider({
    url: Cesium.IonResource.fromAssetId(1),
    geocoder :true,
    infoBox : false,
    sceneModePicker : false,
    selectionIndicator : true,
    timeline : false,
    navigationHelpButton : false,
    scene3DOnly : true
          
  }),
});



var modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(
    Cesium.Cartesian3.fromDegrees(-121.068367, 39.032287, 432.836508));

    var model = viewer.scene.primitives.add(Cesium.Model.fromGltf({
    url : 'scene.gltf',
    modelMatrix : modelMatrix,
    scale : 1.5
}));
console.log(model);
viewer.scene.globe.depthTestAgainstTerrain = true;

var tileset = viewer.scene.primitives.add(
  new Cesium.Cesium3DTileset({
   url: Cesium.IonResource.fromAssetId(700040),
   geocoder :true,
    infoBox : true,
    sceneModePicker : true,
    selectionIndicator : true,
    timeline : false,
    navigationHelpButton : true,
    scene3DOnly : true
  })
);
let pos = {
    x: 1214939.1184933728,
    y: -4736505.884059093,
    z: 4081598.457967,
};

console.log(tileset)

/*** Flag assets
viewer.scene.primitives.add(
  new Cesium.Cesium3DTileset({
   url: Cesium.IonResource.fromAssetId(698752),
   geocoder :true,
    infoBox : false,
    sceneModePicker : false,
    selectionIndicator : true,
    timeline : false,
    navigationHelpButton : false,
    scene3DOnly : true
  })
);
*/

viewer.scene.primitives.add(
  new Cesium.Cesium3DTileset({
   url: Cesium.IonResource.fromAssetId(96188),
   geocoder :true,
    infoBox : false,
    sceneModePicker : false,
    selectionIndicator : true,
    timeline : false,
    navigationHelpButton : false,
    scene3DOnly : true
  })
);


viewer.scene.primitives.add(
  new Cesium.Cesium3DTileset({
    url: Cesium.IonResource.fromAssetId(700077),
    geocoder :true,
    infoBox : false,
    sceneModePicker : false,
    selectionIndicator : true,
    timeline : false,
    navigationHelpButton : false,
    scene3DOnly : true
  })
);



tileset.readyPromise
  .then(function () {
    viewer.zoomTo(tileset);

    // Apply the default style if it exists
    var extras = tileset.asset.extras;
    if (
      Cesium.defined(extras) &&
      Cesium.defined(extras.ion) &&
      Cesium.defined(extras.ion.defaultStyle)
    ) {
      tileset.style = new Cesium.Cesium3DTileStyle(extras.ion.defaultStyle);
    }
  })
  .otherwise(function (error) {
    console.log(error);
  });


  </script>

 </div>

</body>

</html>