type err = [ | `Rejected_sender of Async_smtp.Smtp_reply.t | 
| `No_recipients of rejected_recipients | 
| `Rejected_sender_and_recipients of Async_smtp.Smtp_reply.t * rejected_recipients | 
| `Rejected_body of Async_smtp.Smtp_reply.t * rejected_recipients | 
 ]include sig ... endval sexp_of_err : err ‑> Sexplib.Sexp.tinclude sig ... endval sexp_of_t : t ‑> Sexplib.Sexp.tval to_string : t ‑> stringval ok_or_error : allow_rejected_recipients:bool ‑> t ‑> string Core.Or_error.tval ok_exn : allow_rejected_recipients:bool ‑> t ‑> string