Storage server not available
open-file-storage-read returned 404 Storage server not available. (no trailing “is”).
Why this happens
File points at a server id that no longer exists or cannot be resolved. Sibling Storage server is not available is the longer policy/upload wording (503).
Diagnose and fix
1. Admin: confirm the file’s storage server still exists and is not purged.
2. Transfer the file to an active server if the old one was removed.
3. See This storage server was removed (Phase 55) if the server row is gone.
4. See File has no storage path if the path itself is empty.