# System Errors This page documents all non-JetStream errors that the NATS server can return to clients, routes, gateways, and leafnode connections. ## Authentication and Authorization Errors | Error | Constant | Description | | -------------------------------------- | ---------------------------------------- | ---------------------------------------------------------------------------------------------------------------- | | Authentication expired | `ErrAuthExpired` | An expired authorization due to timeout. | | Proxy is not trusted | `ErrAuthProxyNotTrusted` | An error condition on failed authentication due to a connection from a proxy not in the list of trusted proxies. | | Proxy connection required | `ErrAuthProxyRequired` | An error condition on failed authentication due to a connection not coming from a proxy. | | Authentication timeout | `ErrAuthTimeout` | An error condition on failed authorization due to timeout. | | Authentication error | `ErrAuthentication` | An error condition on failed authentication. | | Credentials have been revoked | `ErrRevocation` | Returned when a credential has been revoked. | | Service import not authorized | `ErrServiceImportAuthorization` | Returned when a service import is not authorized. | | Stream import not authorized | `ErrStreamImportAuthorization` | Returned when a stream import is not authorized. | | Authorization Violation | `Authorization Violation` | Client attempted an operation that violates configured permissions | | User Authentication Expired | `User Authentication Expired` | User JWT or credentials have expired | | Account Authentication Expired | `Account Authentication Expired` | Account authentication has expired | | User Authentication Revoked | `User Authentication Revoked` | User credentials have been revoked | | Permissions Violation for Publish | `Permissions Violation for Publish` | Client attempted to publish to a subject without permission | | Permissions Violation for Subscription | `Permissions Violation for Subscription` | Client attempted to subscribe to a subject without permission | ## Connection Limit Errors | Error | Constant | Description | | ------------------------------------------- | --------------------------------- | ----------------------------------------------------------------------------------------- | | Maximum account active connections exceeded | `ErrTooManyAccountConnections` | That an account has reached its maximum number of active connections. | | Maximum connections exceeded | `ErrTooManyConnections` | A client that the maximum number of connections supported by the server has been reached. | | Maximum subscriptions exceeded | `ErrTooManySubs` | A client that the maximum number of subscriptions per connection has been reached. | | Connection Throttling Is Active | `Connection Throttling Is Active` | Server is actively throttling new connections | | Maximum Clients Exceeded | `Maximum Clients Exceeded` | Server has reached its maximum number of allowed clients | ## Protocol and Payload Errors | Error | Constant | Description | | -------------------------------------- | -------------------------------- | ------------------------------------------------------------------------------- | | Invalid client protocol | `ErrBadClientProtocol` | A client requested an invalid client protocol. | | Bad message header detected | `ErrBadMsgHeader` | The parser detected a bad message header | | Maximum control line exceeded | `ErrMaxControlLine` | An error condition when the control line is too big. | | Maximum payload exceeded | `ErrMaxPayload` | An error condition when the payload is too big. | | Message headers not supported | `ErrMsgHeadersNotSupported` | The parser detected a message header but they are not supported on this server. | | No responders requires headers support | `ErrNoRespondersRequiresHeaders` | That a client needs to have headers on if they want no responders behavior. | | Maximum Payload Violation | `Maximum Payload Violation` | Published message exceeds the configured maximum payload size | | Protocol Violation | `Protocol Violation` | Client violated the NATS protocol | | Parser Error | `Parser Error` | Server encountered an error parsing client protocol | ## Subject and Publishing Errors | Error | Constant | Description | | --------------------------------------------------------------------------- | -------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------- | | Invalid publish subject | `ErrBadPublishSubject` | An error condition for an invalid publish subject. | | Bad qualifier | `ErrBadQualifier` | Used to error on a bad qualifier for a transform. | | Invalid subject | `ErrBadSubject` | An error condition for an invalid subject. | | Invalid mapping destination | `ErrInvalidMappingDestination` | Used for all subject mapping destination errors | | Invalid transform | `ErrInvalidMappingDestinationSubject` | Used to error on a bad transform destination mapping | | Malformed subject | `ErrMalformedSubject` | Returned when a subscription is made with a subject that does not conform to subject rules. | | Wildcard index out of range | `ErrMappingDestinationIndexOutOfRange` | Returned when the mapping destination function is passed an out of range wildcard index value for one of it's arguments | | Function argument is invalid or in the wrong format | `ErrMappingDestinationInvalidArg` | Returned when the mapping destination function is passed and invalid argument | | Not enough arguments passed to the function | `ErrMappingDestinationNotEnoughArgs` | Returned when the mapping destination function is not passed enough arguments | | The only mapping function allowed for import transforms is `{{Wildcard()}}` | `ErrMappingDestinationNotSupportedForImport` | Returned when you try to use a mapping function other than wildcard in a transform that needs to be reversible (i.e. an import) | | Not using all of the token wildcard(s) | `ErrMappingDestinationNotUsingAllWildcards` | Used to error on a transform destination not using all of the token wildcards | | Too many arguments passed to the function | `ErrMappingDestinationTooManyArgs` | Returned when the mapping destination function is passed too many arguments | | No matching transforms available | `ErrNoTransforms` | No subject transforms are available to map this subject. | | Reserved account | `ErrReservedAccount` | A reserved account that can not be created. | | Reserved internal subject | `ErrReservedPublishSubject` | An error condition when sending to a reserved subject, e.g. `_SYS.>` | | Subject has exceeded number of tokens limit | `ErrTooManySubTokens` | A client that the subject has too many tokens. | | Unknown function | `ErrUnknownMappingDestinationFunction` | Returned when a subject mapping destination contains an unknown mustache-escaped mapping function. | | Invalid Subscription | `Invalid Subscription` | Subscription request is invalid | ## TLS and Security Errors | Error | Constant | Description | | -------------------------------- | ---------------------------------- | ------------------------------------------------------------------- | | Certificate not pinned | `ErrCertNotPinned` | Returned when pinned certs are set and the certificate is not in it | | Secure Connection - TLS Required | `Secure Connection - TLS Required` | Server requires TLS but client attempted non-TLS connection | | TLS Handshake Error | `TLS Handshake Error` | TLS handshake with client failed | ## Account Errors | Error | Constant | Description | | ---------------------------------------------------- | --------------------------------- | ---------------------------------------------------------------------------------------------------------- | | Account exists | `ErrAccountExists` | Returned when an account is attempted to be registered but already exists. | | Account expired | `ErrAccountExpired` | Returned when an account has expired. | | Account resolver no new claims | `ErrAccountResolverSameClaims` | Returned when same claims have been fetched. | | Account resolver update too soon | `ErrAccountResolverUpdateTooSoon` | Returned when we attempt an update too soon to last request. | | Account validation failed | `ErrAccountValidation` | Returned when an account has failed validation. | | Bad account | `ErrBadAccount` | A malformed or incorrect account. | | Bad sampling percentage, should be 1-100 | `ErrBadSampling` | Returned when the sampling for latency tracking is not 1 `>=` sample `<=` 100. | | Bad service response type | `ErrBadServiceType` | Returned when latency tracking is being applied to non-singleton response types. | | Import forms a cycle | `ErrImportFormsCycle` | Returned when an import would form a cycle. | | Account missing | `ErrMissingAccount` | Returned when an account does not exist. | | Service missing | `ErrMissingService` | Returned when an account does not have an exported service. | | Account resolver missing | `ErrNoAccountResolver` | Returned when we attempt an update but do not have an account resolver. | | System account not setup | `ErrNoSysAccount` | Returned when an attempt to publish or subscribe is made when there is no internal system account defined. | | Stream import prefix can not contain wildcard tokens | `ErrStreamImportBadPrefix` | Returned when a stream import prefix contains wildcards. | | Stream import already exists | `ErrStreamImportDuplicate` | Returned when a stream import is a duplicate of one that already exists. | | Failed Account Registration | `Failed Account Registration` | Failed to register client with account | ## Server Name and Cluster Errors | Error | Constant | Description | | -------------------------------------------------------------- | ------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- | | Cluster name conflicts between cluster and gateway definitions | `ErrClusterNameConfigConflict` | That the options for cluster name in cluster and gateway are in conflict. | | Cluster name cannot contain spaces | `ErrClusterNameHasSpaces` | That the cluster name contains spaces, which is not allowed. | | Cluster name from remote server conflicts | `ErrClusterNameRemoteConflict` | That a remote server has a different cluster name. | | Duplicate server name | `ErrDuplicateServerName` | Returned when processing a server remote connection and the server reports that this server name is already used in the cluster. | | Gateway name cannot contain spaces | `ErrGatewayNameHasSpaces` | That the gateway name contains spaces, which is not allowed. | | Remote leafnode has same cluster name | `ErrLeafNodeHasSameClusterName` | An error condition when a leafnode is a cluster and it has the same cluster name as the hub cluster. | | Server name cannot contain spaces | `ErrServerNameHasSpaces` | That the server name contains spaces, which is not allowed. | ## Wrong Port Connection Errors | Error | Constant | Description | | -------------------------------------- | ---------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- | | Attempted to connect to leaf node port | `ErrClientConnectedToLeafNodePort` | An error condition when a client attempted to connect to the leaf node listen port. | | Attempted to connect to route port | `ErrClientConnectedToRoutePort` | An error condition when a client attempted to connect to the route listen port. | | Attempted to connect to gateway port | `ErrClientOrRouteConnectedToGatewayPort` | An error condition when a client or route attempted to connect to the Gateway port. | | Attempted to connect to wrong port | `ErrConnectedToWrongPort` | An error condition when a connection is attempted to the wrong listen port (for instance a LeafNode to a client port, etc...) | ## Gateway-Specific Errors | Error | Constant | Description | | ------------------------------ | -------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | Wrong gateway | `ErrWrongGateway` | An error condition when a server receives a connect request from a remote Gateway with a destination name that does not match the server's Gateway's name. | | Connection to Gateway Rejected | `Connection to Gateway Rejected` | Gateway rejected the connection | ## Leafnode-Specific Errors | Error | Constant | Description | | ----------------------------------------------------- | ------------------------------- | ---------------------------------------------------------------------------------------------- | | Leafnodes disabled | `ErrLeafNodeDisabled` | When we disable leafnodes. | | Leafnode loop detected | `ErrLeafNodeLoop` | A leafnode is trying to register for a cluster we already have registered. | | Connection rejected since minimum version required is | `ErrLeafNodeMinVersionRejected` | The leafnode protocol error prefix used when rejecting a remote due to leafnodes.min\_version. | ## Connection State Errors | Error | Constant | Description | | --------------------- | --------------------- | ----------------------------------------------------- | | Connection closed | `ErrConnectionClosed` | An error condition on a closed connection. | | Server is not running | `ErrServerNotRunning` | Used to signal an error that a server is not running. | | Stale Connection | `Stale Connection` | Connection is stale and will be closed | ## Other Errors | Error | Constant | Description | | ------------------------------ | --------------------------------- | -------------------------------------------------------------------- | | Search cycle depth exhausted | `ErrCycleSearchDepth` | Returned when we have exceeded our maximum search depth.. | | Minimum version required | `ErrMinimumVersionRequired` | Returned when a connection is not at the minimum version required. | | Subscribe permission violation | `ErrSubscribePermissionViolation` | Returned when processing of a subscription fails due to permissions. | ## Route-Specific Errors | Error | Constant | Description | | ----------------------------- | ------------------------------- | ---------------------------------------------- | | Route Authorization Violation | `Route Authorization Violation` | Route connection failed authorization | | Duplicate Route | `Duplicate Route` | Route connection already exists to this server | ## Slow Consumer and Flow Control | Error | Constant | Description | | ----------------------- | ------------------------- | ---------------------------------------------------------------------------- | | Slow Consumer Detected | `Slow Consumer Detected` | Server detected a slow consumer that is not keeping up with message delivery | | Consumer Is Slow | `Consumer Is Slow` | Consumer is processing messages too slowly | | Write Deadline Exceeded | `Write Deadline Exceeded` | Write operation to client exceeded the configured deadline | ## Connection Close Reasons These are the reasons a client connection may be closed by the server. They appear in monitoring data and disconnect events. | Error | Constant | Description | | ------------------------------------ | ----------------------------------- | ------------------------------------ | | Client Closed | `ClientClosed` | Client Closed | | Authentication Timeout | `AuthenticationTimeout` | Authentication Timeout | | Authentication Failure | `AuthenticationViolation` | Authentication Failure | | TLS Handshake Failure | `TLSHandshakeError` | TLS Handshake Failure | | Slow Consumer (Pending Bytes) | `SlowConsumerPendingBytes` | Slow Consumer (Pending Bytes) | | Slow Consumer (Write Deadline) | `SlowConsumerWriteDeadline` | Slow Consumer (Write Deadline) | | Write Error | `WriteError` | Write Error | | Read Error | `ReadError` | Read Error | | Parse Error | `ParseError` | Parse Error | | Stale Connection | `StaleConnection` | Stale Connection | | Protocol Violation | `ProtocolViolation` | Protocol Violation | | Bad Client Protocol Version | `BadClientProtocolVersion` | Bad Client Protocol Version | | Incorrect Port | `WrongPort` | Incorrect Port | | Maximum Account Connections Exceeded | `MaxAccountConnectionsExceeded` | Maximum Account Connections Exceeded | | Maximum Connections Exceeded | `MaxConnectionsExceeded` | Maximum Connections Exceeded | | Maximum Message Payload Exceeded | `MaxPayloadExceeded` | Maximum Message Payload Exceeded | | Maximum Control Line Exceeded | `MaxControlLineExceeded` | Maximum Control Line Exceeded | | Maximum Subscriptions Exceeded | `MaxSubscriptionsExceeded` | Maximum Subscriptions Exceeded | | Duplicate Route | `DuplicateRoute` | Duplicate Route | | Route Removed | `RouteRemoved` | Route Removed | | Server Shutdown | `ServerShutdown` | Server Shutdown | | Authentication Expired | `AuthenticationExpired` | Authentication Expired | | Wrong Gateway | `WrongGateway` | Wrong Gateway | | Missing Account | `MissingAccount` | Missing Account | | Credentials Revoked | `Revocation` | Credentials Revoked | | Internal Client | `InternalClient` | Internal Client | | Message Header Violation | `MsgHeaderViolation` | Message Header Violation | | No Responders Requires Headers | `NoRespondersRequiresHeaders` | No Responders Requires Headers | | Cluster Name Conflict | `ClusterNameConflict` | Cluster Name Conflict | | Duplicate Remote LeafNode Connection | `DuplicateRemoteLeafnodeConnection` | Duplicate Remote LeafNode Connection | | Duplicate Client ID | `DuplicateClientID` | Duplicate Client ID | | Duplicate Server Name | `DuplicateServerName` | Duplicate Server Name | | Minimum Version Required | `MinimumVersionRequired` | Minimum Version Required | | Cluster Names Identical | `ClusterNamesIdentical` | Cluster Names Identical | | Kicked | `Kicked` | Kicked | | Proxy Not Trusted | `ProxyNotTrusted` | Proxy Not Trusted | | Proxy Required | `ProxyRequired` | Proxy Required |