Hi @shuzmm
From the error message it seems that the error occurs when building the frontend-2 package. In order to run just the sandbox, you don’t need that.
You have the option of building the viewer’s required packages individually by running yarn build inside the viewer, object-loader and shared packages, then run yarn dev inside the viewer-sandbox package. This will start a local dev server on http://localhost:3033/ where the sandbox will be running.
Let me know if you need more help
Cheers