Did you set your statesetId value in the following code block in your web app:
const tilesetId = "<tilesetId>";
const statesetId = "<statesetId>";
const indoorManager = new atlas.indoor.IndoorManager(map, {
tilesetId: tilesetId,
statesetId: statesetId // Optional
});
if (statesetId.length > 0) {
indoorManager.setDynamicStyling(true);
}