Mandatory Field Error
Category: Format & data Initiated by: RDFI
Read reinitiation conditions and source →Applies to (SEC scope)
ALL
camt.053 mapping
FF02 — Syntax Error
ISO code shared with other Nacha codes
Nacha's definition
Erroneous data or missing data in a mandatory field.
Verbatim from Nacha — ISO 20022 Guide to Mapping U.S. ACH Return Items and Notifications of Change, August 2023, Version 2.01 (Table 1, return reason codes) (return reason code table). Applies to: ALL.
Reinitiation conditions
Nacha's reinitiation rule page allows reinitiation "to correct administrative errors", with fields other than Company Name, Company ID and Amount modified only to the extent necessary. A corrected resubmission of a returned debit is therefore treated as a reinitiation, within the Rules' limits and carrying RETRY PYMT. Nacha's reinitiation rule addresses returned debits; a returned credit falls outside it.
correct the field the RDFI identified, and code the resubmission correctly.
How it appears in an ISO 20022 statement
Nacha's mapping guide maps R26 to camt.053 reason code FF02 (Syntax Error) — ISO definition: Syntax error reason is provided as narrative information in the additional reason information. Nacha marks this ISO code as mapped to more than one Nacha return code, so the ISO code alone does not identify the Nacha reason; read the narrative or the original return record.
Return time frame
Nacha's public rule pages refer to the standard "two-day" return time frame for returns that are not extended (unauthorized) returns. The current Nacha Operating Rules and your ODFI determine the applicable deadline for this code; a general public two-day reference is not a substitute for that code-specific requirement.
What an operator does next
A mandatory field is missing or erroneous. The RDFI will identify the field; correct it in the record.
PaymentBrief guidance, not Nacha text. Your ODFI's procedures and the current Nacha Operating Rules govern.
Where this comes up on PaymentBrief
Sources for this code
- Nacha — ISO 20022 Guide to Mapping U.S. ACH Return Items and Notifications of Change, August 2023, Version 2.01 (Table 1, return reason codes) — retrieved 2026-09-06
- Nacha — rule page 'ACH Network Risk and Enforcement Topics' (unauthorized return rate threshold; reinitiation of entries) — retrieved 2026-09-06