Reseller top-up presets must be a JSON array
Presets setting failed the array-type check (not a JSON array at all).
Why this happens
Value is an object, string, or invalid JSON. Stricter sibling requires dollar amount elements once it is an array.
Diagnose and fix
1. Replace the setting with a JSON array (then use numeric dollar amounts).
2. Save and retest reseller top-up.
3. If amounts are wrong shape, see the “dollar amounts” article.
4. Member-facing amount errors are separate (Select a valid top-up amount).