Each custom payout method needs a name
Saving payout method config failed validation (payout-method-config) because a custom method has an empty name.
Why this happens
Admin added a custom payout method row without a label. Built-in methods are fine; custom ones require a name.
Diagnose and fix
1. Open Payout method definitions / Affiliation payout settings.
2. Give each custom method a clear name; remove empty rows.
3. Save again.
4. Members only see named, enabled methods on Request a payout.