I've seen a few posts here around this issue but none are leading me to a solution. I'm using Assets with an S3 bucket and have moved EE to a new server. The front-end of the site loads right up just fine, but all thumbs in the CMS are missing. I've tried using "Update Indexes" and it seems to complete fine but when going back to the "Assets / File Manager" screen the thumbnails are still missing.
We intentionally didn't move the cache folder over to the new server because we're trying to keep images out our Git repo.
Suggestions on how I might fix this?