Just notice the new app store is launched. I am trying to preview the asset page for a draft assets. But seem it is not working. It direct to front page of new asset store.
I have the same problem
Now it works properly.
I find it odd that we can no longer preview logo and small image in the preview.
However, I found a way to view assets in the old preview layout by manipulating the link slightly.
Old Preview:
https://www.assetstore.unity3d.com/en/?stay#!/preview/[your preview number]
New Preview
https://assetstore.unity.com/preview/[your preview number]