Notes error: You cannot update or delete the document(s) since you are not listed as an allowable Author for this document

Hi, I have an agent to save a notes document at backend, the first save was successful, but if I do a second save, I got this error: Notes error: You cannot update or delete the document(s) since you are not listed as an allowable Author for this document

The agent ID has Manager to access the db, can anybody help me what is wrong with it? thanks a lot,

Subject: Authors fields

The document that you are saving has one or more Authors fields on it.

Those fields determine who can edit the document. For some reason you (or the agent) is not in the Authors field and thus are not allowed to edit the document.