Lemon Squeezy checkout is not configured
Plan/traffic checkout selected Lemon Squeezy while it is not ready (balanceTopUp.lemonSqueezyNotConfigured / 503).
Why this happens
Same family as Coinbase/BTCPay short “not configured” — credentials or enable flag incomplete.
Diagnose and fix
1. Enable Lemon Squeezy checkout; fill API key, store ID, variant ID.
2. Retry premium/traffic purchase; member should redirect to Lemon Squeezy.
3. Offer Stripe/PayPal/etc. if Lemon Squeezy is not intentional.
4. Longer sibling includes the Admin path explicitly.