This looks like a sync/display issue between Vapi and ElevenLabs, not a problem with your API key.
The fact that default voices show when the key is removed, but nothing appears when it’s added (even though the API is being hit), usually means Vapi isn’t properly mapping or rendering your ElevenLabs voices in the UI.
The “voice already exists” message confirms the voices are actually being detected in the backend it’s just not reflecting in the Voice Library.
This has come up before and is typically a platform-side issue. I can help you verify it quickly from logs or test calls if you want to be 100% sure before escalating it.
@kevinmtu