# COB troubleshooting
Source: https://www.stedi.com/docs/healthcare/cob-troubleshooting

***

title: COB troubleshooting
sidebarTitle: "Troubleshooting"
-------------------------------

A list of potential errors and possible resolutions when submitting coordination of benefits (COB) checks.

## Inaccurate patient data

COB checks are significantly more sensitive to data accuracy than eligibility checks. To perform successful COB checks, the patient information you provide in the check **must** match the payer's data exactly.

For example, if a payer has a patient's name stored as "Jonathan Doe", they may return benefits information when you submit an eligibility check for "Jon Doe", as long as they can identify the patient through the other information provided. However, a COB request for "Jon Doe" will fail because the name doesn't match the payer's records exactly.

To avoid unnecessary COB check failures, we strongly recommend that you first submit an eligibility check request for the patient. Then use the following data from the successful eligibility response to build the COB request: `firstName`, `lastName`, `dateOfBirth`, `memberId`.

## Invalid or unsupported payer ID

COB requests require a valid payer ID in the `tradingPartnerServiceId` property. Visit the Stedi [Payer Network](https://www.stedi.com/healthcare/network?query=eyIyNzAiOnt9LCIyNzYiOnt9LCI4MzUiOnt9LCI4MzdQIjp7fSwiODM3SSI6e30sIjgzN0QiOnt9LCJDT0IiOnsiaXNTdXBwb3J0ZWQiOnRydWV9fQ%3D%3D\&page=0) for a complete list of supported payers and their payer IDs.

You should also ensure that you're sending the request to the correct payer entity. For example, Blue Cross Blue Shield (BCBS) has multiple entities that operate in different states. If you send a request to the wrong entity, the request will fail with an `AAA` = `75` error (Subscriber/Insured Not Found).

## Missing data

COB requests must contain the patient’s `firstName`, `lastName`, `dateOfBirth`, plus `memberId` and/or `ssn`. If you do not send all data points, Stedi returns an HTTP `400` error with a message listing the missing data.

{/* schema:ValidationExceptionResponseContent */}

```json
{
  "fieldList": [
    {
      "path": "/subscriber/dateOfBirth",
      "message": "Value at '/subscriber/dateOfBirth' failed to satisfy constraint: Member must not be null"
    }
  ],
  "message": "1 validation error detected. Value at '/subscriber/dateOfBirth' failed to satisfy constraint: Member must not be null"
}
```

## Request found multiple patients

The `Duplicate Subscriber/Insured ID Number` error can occur when Stedi finds more than one member ID for the patient in the request. For example, this could occur if you only provide the patient's Social Security Number (SSN), and the search returns more than one member ID associated with that SSN.

In this case, Stedi returns a HTTP `200` response with an `AAA` error in the `subscriber` object.

{/* schema:COBResponseSubscriber:unwrap */}

```json
"subscriber": {
  "memberId": "123456789",
  "firstName": "John",
  "lastName": "Doe",
  "dateOfBirth": "1961-10-21",
  "aaaErrors": [
    {
      "field": "AAA",
      "code": "76",
      "description": "Duplicate Subscriber/Insured ID Number",
      "followupAction": "Please Correct and Resubmit",
      "location": "Loop 2100C",
      "possibleResolutions": "Duplicate member ID was found in the payer database."
    }
  ]
}
```

## Member not found

If Stedi cannot find a member ID for the patient in the request, it returns an HTTP `200` response with an `AAA` error in the `subscriber` object.

{/* schema:COBResponseSubscriber:unwrap */}

```json
"subscriber": {
  "memberId": "123456789",
  "firstName": "John",
  "lastName": "Doe",
  "dateOfBirth": "1961-10-21",
  "aaaErrors": [
    {
      "field": "AAA",
      "code": "75",
      "description": "Subscriber/Insured Not Found",
      "followupAction": "Please Correct and Resubmit",
      "location": "Loop 2100C",
      "possibleResolutions": "- Subscriber was not found."
    }
  ]
}
```

Mismatches in the `memberId` are one of the most common causes of `Subscriber/Insured Not Found` errors. We strongly recommend first performing an eligibility check and using the `memberId` in the response to populate your COB check.

You will also receive a `Subscriber/Insured Not Found` error if you try to submit a COB check to a Medicare or Medicare Advantage plan. These plans aren't supported for COB checks.

## Invalid service dates

The service dates you provide **must** be within the past 2 years. COB checks don't support requests with dates outside of this range.

Don't send service dates that are in the future. Future service dates typically result in errors from the payer.

## Inactive coverage

For COB checks to return a positive result, the patient must have active coverage. Sometimes, you can receive a false negative or error on a COB check when a patient's coverage has very recently changed. For example, if the patient recently became eligible for coverage within the last few days, that information may not yet be reflected in the COB member data, and you will receive a `Subscriber/Insured Not Found` error.

Payers typically update COB member data on a weekly basis. If you receive an error and the patient's coverage has recently changed, we recommend trying again next week to give the changes time to propagate to the COB database.

## AAA errors

The COB response may contain one or more `AAA` errors specify issues with your request and any recommended follow-up actions. Stedi includes this information in the `aaaErrors` object in the response JSON.

`AAA` errors can be present at multiple different levels in the response, depending on the type. In the COB response, the `subscriber`, `dependent`, and `provider` objects can each contain their own `aaaErrors` array.

Common causes for AAA errors include:

* Missing or incorrect information for the subscriber, dependent, provider, or payer. In this case, you should correct any errors before resubmitting.
* Issues with payer enrollment. Many of these issues require that the provider contact the payer directly to resolve, due to PHI/HIPAA guidelines.

Each error contains a code field that corresponds to a `followupAction`:

* `C` - Please correct and resubmit
* `N` - Resubmission not allowed
* `P` - Please resubmit original transaction
* `R` - Resubmission allowed
* `S` - Do not resubmit; Inquire initiated to a third party
* `Y` - Do not resubmit; We will hold your request and respond again shortly