Paddle checkout is not configured
Plan, traffic, or reseller top-up selected Paddle while it is not ready (balanceTopUp.paddleNotConfigured / 503).
Why this happens
Same family as NOWPayments/Lemon Squeezy short “not configured” — credentials or enable flag incomplete. Distinct from the marketing-page string Paddle checkout is not configured on this site.
Diagnose and fix
1. Enable Paddle checkout; fill API credentials; save.
2. Retry premium/traffic purchase; member should redirect to Paddle.
3. Offer another gateway if Paddle is not intentional.
4. Longer sibling includes the Admin path explicitly.