| Code | Display | Definition |
| ACCESS_DENIED | Access has been denied to process this request | Used when the user does not have permission for a particular request. e.g. when their ASID does not have the correct interactions attached to it. |
| FAILURE_TO_PROCESS_MESSAGE | Failure to process message | A default message when something really bad has happened that the system could not handle. |
| UNABLE_TO_CALL_SERVICE | Unable to call service | For a synchronous request, the downstream domain processing has not completed within the configured timeout period. |
| UNSUPPORTED_SERVICE | Unsupported service | The service the user requested is an endpoint that does not exist - so is unsupported. e.g. /Patient/9999999999/Pets |
| RESOURCE_NOT_FOUND | Resource not found | The resource was not found. |
| INVALID_RESOURCE_ID | Invalid resource ID | The resource ID was not valid. For example a NHS Number is presented which is not a valid NHS Number. |
| INVALIDATED_RESOURCE | Invalidated resource | The resource has been invalidated so could not be returned. |
| INVALID_SEARCH_DATA | Invalid search data | The search parameters are invalid. A description of what exactly is at fault will be added to the display. |
| TOO_MANY_MATCHES | Too many matches | Too many matches were found - user should refine their search parameters. |
| PRECONDITION_FAILED | Precondition failed | Request missing basic requirements such as If-Match header (or invalid headers). |
| RESOURCE_VERSION_MISMATCH | Resource version mismatch | The resource version has changed since your last read, so the update has been rejected. |
| FORBIDDEN_UPDATE | Forbidden update | The user is not permitted to update certain resources or elements - a detailed description will be added to the display. For example - updating a sensitive patient or adding a formal death notification is only permitted from certain systems. |
| VALIDATION_ERROR | Validation error | This it the 'default' error thrown when no others are applicable. |
| INVALID_UPDATE | Invalid update | The update was invalid - a detailed description will be added to the display. |
| MISSING_VALUE | Missing value | There was a missing value in the request. For example - a name update that is missing the surname. The missing value will be presented in the display. |
| INVALID_VALUE | Invalid value | There was an invalid value in the request. For example - a name update where the surname is too long. The invalid value and field will be presented in the display. |
| UNSUPPORTED_VALUE | Unsupported value | There was an unsupported value in the request. The value may be valid in the schema - however it could be a legacy value that we do not allow to be set anymore. For example - setting the death notification status to 'removed'. The invalid value and field will be presented in the display. |
| TOO_FEW_VALUES_SUBMITTED | Too few values submitted | The field in question has a minimum number of items and the user sent too few. |
| TOO_MANY_VALUES_SUBMITTED | Too many values submitted | The field in question has a maximum number of items and the user sent too many. |
| ADDITIONAL_PROPERTIES | Additional properties | The user sent additional properties within the dictionary. For example sending a patient patch and attempting to add 'pets', which is not an allowed field within the patient resource. |
| POLLING_ID_NOT_FOUND | Polling ID not found | When polling the ID was not found - or it was not applicable such as a non polling ID. |
| POLLING_MESSAGE_FAILURE | Polling message failure | When polling an ID, a message was found to be in a failed state, so there is nothing else to be done and should be considered a failure. |
