Recognize file-storage failures

Message bodies and attachments use authenticated storage. A visible database row does not prove that its file object is available.

Symptom	Next action
Connection refused	Ask the operator to check this instance's SeaweedFS service and endpoint.
Anonymous request returns 403	The store requires authentication. Keep the bucket private.
Body missing after a move between installations	Check object transfer and canonical object references.
Encrypted content needs a key	Use the correct owner's existing key to open the content in the application.

SeaweedFS is S3-compatible but does not implement every AWS feature. Correcting a connection does not require mailbox or storage deletion. See local storage.