why AudioComponentInstanceNew return -1

AudioComponentDescription desc = {kAudioUnitType_Output,
                                  kAudioUnitSubType_VoiceProcessingIO,
                                  kAudioUnitManufacturer_Apple, 
                                  0, 0};
AudioComponent comp = AudioComponentFindNext(NULL, &desc);
OSStatus error = AudioComponentInstanceNew(comp, &myAudioUnit);

In special case the returned error value is -1, I searched the https://www.osstatus.com/, but didn't get relevent info.

my question is:

1. what's the meanning of -1 in the case ?
2. myAudioUnit is a nullptr this time ?