Error 90108 — Quantity is invalid or below minimum

The quantity you submitted is invalid — negative, non-numeric, zero where stock is required, or exceeds Amazon's allowed maximum (typically 10,000 per SKU per warehouse).

Quantity must be a positive integer. FBA SKUs draw from inventory that Amazon manages directly, so submitting a quantity for an FBA SKU also triggers this error.

1. For Merchant-Fulfilled (FBM) SKUs: submit a positive integer for quantity.
2. For FBA SKUs: don't submit quantity in your feed — Amazon manages it from inbound shipments.
3. If the quantity is correct but flagged, check that the SKU's fulfillment_channel is set correctly (DEFAULT for FBM, AMAZON_NA for FBA).

• Submitting quantity = 0 instead of just leaving the SKU out of the feed — sets stock to 0 explicitly
• Including quantity for FBA SKUs — Amazon ignores it but the error appears