Invalid affiliate program sections payload
Admin /api/admin/design/pages/affiliate-program/sections rejected the body (400 Invalid affiliate program sections payload.).
Why this happens
Malformed JSON, missing required section fields, or a client/UI bug sending an incomplete sections array. Not a member affiliation error.
Diagnose and fix
1. Reload the Affiliate program page designer; undo recent bad edits.
2. Save again with a complete sections payload from the UI (avoid hand-crafted API calls).
3. Check admin network tab for the validation response details if any.
4. See Affiliate program page design.