Feature not enabled
feature_not_enabled
The account's plan does not include this capability at all. This is not a spent budget — it is a capability the plan never had, which is why it is a 403 and not a 429.
Why it happens
Calling a generation endpoint from an account with no active VoiceLabs subscription or trial, once the free allowance no longer applies.
How to fix it
Upgrade the account. The problem document carries a settings_url pointing straight at the billing page for the account that made the call, and entitlement takes effect immediately — the next request succeeds.
Safe to retry?
No, and waiting does not help either: unlike quota_exhausted, this one does not reset at the start of the month.
What it looks like on the wire
{
"type": "https://voicelabs.now/errors/feature_not_enabled",
"title": "Feature not enabled",
"status": 403,
"detail": "A human-readable explanation of this particular occurrence.",
"instance": "/v1/speech",
"code": "feature_not_enabled"
}
Branch on code, never on status or on the prose in detail: two different problems can share a status, and detail is written for humans and may be reworded. Problems a settings page can resolve also carry settings_url, and a scope failure carries required_scope.
Every VoiceLabs API error is an RFC 9457 problem document with a stable code.