Sorry, I didn’t pick up on that. I don’t know, unless something’s interfering with communication in the matching process. You might check the logs after trying to match, or post them here so someone can look at them, to see if there are any clues.
You might also try using the MusicBrainz Artist MBID to make sure it’s finding the correct match.
Nirvana MBID: 5b11f4ce-a62d-471e-81fc-a69a8278c7da
If you’re not familiar with doing that, I explained it to someone else here: