| Lvl | Code | Display | Definition | 
| 1 | 
invalid  | 
Invalid Content | 
Content invalid against the specification or a profile. | 
| 2 | 
  structure  | 
Structural Issue | 
A structural issue in the content such as wrong namespace, unable to parse the content completely, invalid syntax, etc. | 
| 2 | 
  required  | 
Required element missing | 
A required element is missing. | 
| 2 | 
  value  | 
Element value invalid | 
An element or header value is invalid. | 
| 2 | 
  invariant  | 
Validation rule failed | 
A content validation rule failed - e.g. a schematron rule. | 
| 1 | 
security  | 
Security Problem | 
An authentication/authorization/permissions issue of some kind. | 
| 2 | 
  login  | 
Login Required | 
The client needs to initiate an authentication process. | 
| 2 | 
  unknown  | 
Unknown User | 
The user or system was not able to be authenticated (either there is no process, or the proferred token is unacceptable). | 
| 2 | 
  expired  | 
Session Expired | 
User session expired; a login may be required. | 
| 2 | 
  forbidden  | 
Forbidden | 
The user does not have the rights to perform this action. | 
| 2 | 
  suppressed  | 
Information  Suppressed | 
Some information was not or might not have been returned due to business rules, consent or privacy rules, or access permission constraints.  This information may be accessible through alternate processes. | 
| 1 | 
processing  | 
Processing Failure | 
Processing issues. These are expected to be final e.g. there is no point resubmitting the same content unchanged. | 
| 2 | 
  not-supported  | 
Content not supported | 
The interaction, operation, resource or profile is not supported. | 
| 2 | 
  duplicate  | 
Duplicate | 
An attempt was made to create a duplicate record. | 
| 2 | 
  multiple-matches  | 
Multiple Matches | 
Multiple matching records were found when the operation required only one match. | 
| 2 | 
  not-found  | 
Not Found | 
The reference provided was not found. In a pure RESTful environment, this would be an HTTP 404 error, but this code may be used where the content is not found further into the application architecture. | 
| 3 | 
    deleted  | 
Deleted | 
The reference pointed to content (usually a resource) that has been deleted. | 
| 2 | 
  too-long  | 
Content Too Long | 
Provided content is too long (typically, this is a denial of service protection type of error). | 
| 2 | 
  code-invalid  | 
Invalid Code | 
The code or system could not be understood, or it was not valid in the context of a particular ValueSet.code. | 
| 2 | 
  extension  | 
Unacceptable Extension | 
An extension was found that was not acceptable, could not be resolved, or a modifierExtension was not recognized. | 
| 2 | 
  too-costly  | 
Operation Too Costly | 
The operation was stopped to protect server resources; e.g. a request for a value set expansion on all of SNOMED CT. | 
| 2 | 
  business-rule  | 
Business Rule Violation | 
The content/operation failed to pass some business rule and so could not proceed. | 
| 2 | 
  conflict  | 
Edit Version Conflict | 
Content could not be accepted because of an edit conflict (i.e. version aware updates). (In a pure RESTful environment, this would be an HTTP 409 error, but this code may be used where the conflict is discovered further into the application architecture.). | 
| 2 | 
  limited-filter  | 
Limited Filter Application | 
Some search filters might not have applied on all results.  Data may have been included that does not meet all of the filters listed in the `self` `Bundle.link`. | 
| 1 | 
transient  | 
Transient Issue | 
Transient processing issues. The system receiving the message may be able to resubmit the same content once an underlying issue is resolved. | 
| 2 | 
  lock-error  | 
Lock Error | 
A resource/record locking failure (usually in an underlying database). | 
| 2 | 
  no-store  | 
No Store Available | 
The persistent store is unavailable; e.g. the database is down for maintenance or similar action, and the interaction or operation cannot be processed. | 
| 2 | 
  exception  | 
Exception | 
An unexpected internal error has occurred. | 
| 2 | 
  timeout  | 
Timeout | 
An internal timeout has occurred. | 
| 2 | 
  incomplete  | 
Incomplete Results | 
Not all data sources typically accessed could be reached or responded in time, so the returned information might not be complete (applies to search interactions and some operations). | 
| 2 | 
  throttled  | 
Throttled | 
The system is not prepared to handle this request due to load management. | 
| 1 | 
informational  | 
Informational Note | 
A message unrelated to the processing success of the completed operation (examples of the latter include things like reminders of password expiry, system maintenance times, etc.). | 
| 1 | 
success  | 
Operation Successful | 
The operation completed successfully. |