Errors

Errors

Errors from the error event and from promise rejections are Error objects with extra fields:

Field	Type	Description
message	string	Readable description
code	number | string	Numeric platform code, or a string code from the library
domain	string	Where code comes from (table below)
serviceName	string?	The service concerned, when there is one

Domains

domain	Platform	code
'DNSSD'	iOS	DNSServiceErrorType from Apple's dns_sd API (negative number)
'DNSSD'	Android (implType: 'DNSSD')	DNSServiceErrorType from the embedded mDNSResponder
'NsdManager'	Android (implType: 'NSD')	NsdManager failure code
'Windows'	Windows	Win32 or DNS_STATUS code from the Windows DNS-SD functions, message has the system description
'RNZeroconf'	all	String code from the library

Common codes

Domain	Code	Meaning
DNSSD	-65555	kDNSServiceErr_NoAuth. iOS: the service type is missing from NSBonjourServices ("not authorized, add the service type to NSBonjourServices in Info.plist"). Also returned by scanServiceTypes() on iOS without the multicast entitlement, see Listing service types
DNSSD	-65570	kDNSServiceErr_PolicyDenied. iOS: Local Network access denied
DNSSD	-65548	kDNSServiceErr_NameConflict, name already in use
DNSSD	-65540	kDNSServiceErr_BadParam
DNSSD	-65554	kDNSServiceErr_NoSuchRecord
DNSSD	-65563	kDNSServiceErr_ServiceNotRunning, mDNS daemon not running
DNSSD	-65568	kDNSServiceErr_Timeout
NsdManager	0	FAILURE_INTERNAL_ERROR
NsdManager	3	FAILURE_ALREADY_ACTIVE
NsdManager	4	FAILURE_MAX_LIMIT, too many requests
NsdManager	5	FAILURE_OPERATION_NOT_RUNNING (API 34+)
NsdManager	6	FAILURE_BAD_PARAMETERS (API 34+)
NsdManager	7	FAILURE_PERMISSION_DENIED (API 37+): the app needs ACCESS_LOCAL_NETWORK, see Permissions and Setup
RNZeroconf	'EXCEPTION'	Unexpected native exception, see message
RNZeroconf	'NOT_PUBLISHED'	unpublishService() with a name that is not published
RNZeroconf	'TIMEOUT'	A scan could not resolve a service within resolveTimeout (after one retry), or resolveService() got no answer within timeout
RNZeroconf	'UNKNOWN_INTERFACE'	The networkInterface passed doesn't exist
RNZeroconf	'UNSUPPORTED'	Android NSD before Android 13: networkInterface is not supported, use DNSSD. Windows: publishing with subtypes
RNZeroconf	'TXT_ENTRY_TOO_LONG'	iOS: a TXT entry over 255 bytes was left out
RNZeroconf	'MISSING_BONJOUR_SERVICES'	iOS: checkLocalNetworkAccess() has no type to test with

zeroconf.on('error', error => {
  if (error.domain === 'DNSSD' && error.code === -65555) {
    // iOS: add the service type to NSBonjourServices
  } else if (error.domain === 'DNSSD' && error.code === -65570) {
    // iOS: Local Network access denied, send the user to Settings
  }
})

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See Error Handling for how to react to them.