SMS_NOT_CONFIGURED
HTTP 503No
No SMS vendor key in the pool (twilio/tencent_sms/aliyun_sms); browser phone OTP cannot be delivered. Config gap, not a transient outage.
By default a failed call returns a result with an error instead of throwing, so your business flow is never interrupted.
Published error codes are permanent: their meaning never silently changes, and deprecated codes keep returning for at least 12 months.