{"record":{"id":"9733a23f2e34026d","repo":"nats-io/nats-server","slug":"no-responders-requires-headers-support","errorCode":null,"errorMessage":"no responders requires headers support","messagePattern":"no responders requires headers support","errorType":"error_code","errorClass":null,"httpStatus":null,"severity":"error","filePath":"server/errors.go","lineNumber":189,"sourceCode":"\t// ErrRevocation is returned when a credential has been revoked.\n\tErrRevocation = errors.New(\"credentials have been revoked\")\n\n\t// ErrServerNotRunning is used to signal an error that a server is not running.\n\tErrServerNotRunning = errors.New(\"server is not running\")\n\n\t// ErrServerNameHasSpaces signals that the server name contains spaces, which is not allowed.\n\tErrServerNameHasSpaces = errors.New(\"server name cannot contain spaces\")\n\n\t// ErrBadMsgHeader signals the parser detected a bad message header\n\tErrBadMsgHeader = errors.New(\"bad message header detected\")\n\n\t// ErrMsgHeadersNotSupported signals the parser detected a message header\n\t// but they are not supported on this server.\n\tErrMsgHeadersNotSupported = errors.New(\"message headers not supported\")\n\n\t// ErrNoRespondersRequiresHeaders signals that a client needs to have headers\n\t// on if they want no responders behavior.\n\tErrNoRespondersRequiresHeaders = errors.New(\"no responders requires headers support\")\n\n\t// ErrClusterNameConfigConflict signals that the options for cluster name in cluster and gateway are in conflict.\n\tErrClusterNameConfigConflict = errors.New(\"cluster name conflicts between cluster and gateway definitions\")\n\n\t// ErrClusterNameRemoteConflict signals that a remote server has a different cluster name.\n\tErrClusterNameRemoteConflict = errors.New(\"cluster name from remote server conflicts\")\n\n\t// ErrClusterNameHasSpaces signals that the cluster name contains spaces, which is not allowed.\n\tErrClusterNameHasSpaces = errors.New(\"cluster name cannot contain spaces\")\n\n\t// ErrClusterNameReserved signals that the cluster name is reserved for internal protocol use.\n\tErrClusterNameReserved = errors.New(\"cluster name is reserved\")\n\n\t// ErrMalformedSubject is returned when a subscription is made with a subject that does not conform to subject rules.\n\tErrMalformedSubject = errors.New(\"malformed subject\")\n\n\t// ErrSubscribePermissionViolation is returned when processing of a subscription fails due to permissions.\n\tErrSubscribePermissionViolation = errors.New(\"subscribe permission violation\")","sourceCodeStart":171,"sourceCodeEnd":207,"githubUrl":"https://github.com/nats-io/nats-server/blob/3a66a489d262bf89b71a71c955c94920394532f3/server/errors.go#L171-L207","documentation":"The client expects no-responders behavior but did not negotiate header support, so the server cannot deliver the 503 no-responders status message on the reply subject. Detected in the publish path; the server sends -ERR and closes the connection with NoRespondersRequiresHeaders.","triggerScenarios":"Thrown at server/errors.go:189 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Enable headers in the client connection options before requesting no-responders","Disable no-responders detection in the client if headers cannot be used","Upgrade the client library to one that negotiates headers automatically"],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"3a66a489d262bf89b71a71c955c94920394532f3","analyzedAt":"2026-09-02T04:41:54.247Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}