Checkout could not be started — try again
Premium or balance top-up UI could not begin checkout (premium.checkoutStartFailed / mapped checkoutStartFailed). Fallback when the start API fails without a clearer message.
Why this happens
Network error, gateway not configured, validation failure, or server 4xx/5xx without a mapped string. Distinct from Checkout cancelled (user abandoned hosted page) and from tier-unavailable messaging.
Diagnose and fix
1. Hard refresh; retry once; check DevTools for the real API error.
2. Admin: confirm at least one payment method is enabled for that product.
3. Member: try another gateway if offered.
4. See gateway-specific “not configured” articles (Authorize.net, Stripe, Coinbase, etc.).