ISRC through API call

MusicBrainz Development
1

I’m trying to get an ISRC of a recording, but somewhere it don’t work.

String recordingID = 3ec90fca-c135-4819-8e3a-98c443ef522f;
Recording rec = client.recording().withId(UUID.fromString(recordingID))
                      .lookup().get();
String recordingTitle = rec.getTitle();
System.out.println(rec.getIsrcList());
if (rec.getIsrcList()!=null ) {
	System.out.println(rec.getIsrcList().getIsrc());
}

I’ve looked online, this MBID has a ISRC. The rec.getIsrcList() ever gets null. What I’m doing wrong?