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N404 Remark Code: Incomplete Facility Certification

N404 means the payer received documentation of the facility's certification, but it was incomplete or invalid, for example expired, for a different location, or missing the certification number or dates.

Quick facts

Code
N404 (RARC N404)
Status
Active In use since August 1, 2007.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim stays denied until valid certification is shown. The provider or facility is responsible; the patient is not billed.
Official description
Incomplete/invalid facility certification.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N404 means

N404 follows a review of the certification you sent. The payer found a problem with the document itself. The facility may well be certified; the paperwork just didn’t prove it for this service, site, and date.

It usually comes with CARC 251, or CARC B7 when the payer concludes the facility wasn’t certified on the date of service.

Where certifications fall short

  • Dates. The certificate’s effective period doesn’t include the date of service, often because an old copy was sent after a renewal.
  • Location. The address on the certificate differs from the service facility on the claim.
  • Entity name. A name change, merger, or new tax ID isn’t reflected on the document.
  • Scope. The certification covers different services, modalities, or test complexity than what was billed.
  • Missing details. No certificate number, issuing body, or signature is visible.

Steps to resolve

  1. Ask the payer exactly which element failed its review.
  2. Pull the certificate version in effect on the date of service, along with any renewal or amendment letters.
  3. If the location or name differs, include documentation connecting them (for example, a change-of-address notice from the certifying body).
  4. Confirm the claim’s service facility and billing details match the certified entity. If they don’t, submit a corrected claim with frequency code 7.
  5. Send the documents through the reconsideration or attachment process with the claim number.

How to prevent it

Maintain one current certification file per site and scope, and give payers updated copies after every renewal or change. Check that your claim templates use the same facility name and address that appear on each certificate.

Codes that may appear with N404

  • CO-251 (The attachment/other documentation that was received was incomplete or deficient.): The attachment received was incomplete or deficient.
  • CO-B7 (This provider was not certified/eligible to be paid for this procedure/service on this date of service.): The provider was not certified or eligible to be paid for this service on the date of service.
  • N403 (Missing facility certification.): Used when no facility certification was received.
  • N474 (Incomplete/invalid certification.): Covers an incomplete or invalid certification in general.
  • N110 (This facility is not certified for film mammography.): States the facility is not certified for film mammography.

N404 FAQ

Why would a valid certificate be called invalid?

It may not cover the date of service, list a different address or entity name, or be a type of certification that doesn't apply to the service billed.

What if our certification lapsed briefly?

Services during a lapse generally can't be supported by the certificate. Check with the payer whether any grace provisions apply.

Do I need to resubmit the claim?

Usually you send the corrected certification through the payer's reconsideration or attachment process. Resubmit the claim only if the payer tells you to or if claim data, such as the service location, was wrong.