Amazon's FBA inbound receiving team processes tens of thousands of shipments per day. They're efficient, they're fast, and they don't have time to troubleshoot your carton. If something's wrong, they bounce it — and you eat the return shipping plus 2–3 weeks of lost selling time.
Here are the seven mistakes we see most often, in rough order of frequency.
1. Crooked or partial FNSKU labels
What Amazon wants: FNSKU barcode, cleanly printed, flat on a smooth surface, scannable on the first try.
What we see: labels applied over curved surfaces (causing scan errors), labels that wrap around edges (unscannable), labels applied over Manufacturer barcodes (Amazon requires the FNSKU to cover the UPC, not sit next to it).
Fix: Use thermal printer, not inkjet (bleeds). Apply to a flat face. For curved bottles or tubes, use a flat label panel or consider a transparent polybag with the label on the bag.
2. Missing suffocation warnings
What Amazon wants: If your product is poly-bagged with a bag opening of 5 inches or larger, the bag must have a suffocation warning in 36-point or larger text.
What we see: generic polybags without warnings, warnings in tiny text, warnings on the wrong side of the bag.
Fix: Order polybags with pre-printed warnings from a reputable supplier. Don't improvise with warning stickers applied in the warehouse — Amazon's scanners sometimes miss them.
3. Expired or near-expiration inventory
What Amazon wants: At least 90–105 days of shelf life remaining on receipt for consumables. Cosmetics need 365+ days.
What we see: sellers shipping inventory with 60 days left "because it's still good." Amazon rejects these and they sit in your FBA returns queue.
Fix: Check expiration dates at your warehouse (or your 3PL's warehouse) before shipping to Amazon. Anything within 90 days of expiry: sell via Multi-Channel Fulfillment, not FBA. Or donate/dispose if resale isn't viable.
4. Bundle SKUs without new FNSKU
What Amazon wants: A bundle is a new SKU. It needs its own FNSKU barcode applied to the outside of the bundle packaging, covering any individual UPCs.
What we see: sellers shipping bundles using the original FNSKU of one of the component items. Amazon receives the bundle but counts it as just the one item.
Fix: Create a new ASIN for every bundle. Get the bundle's unique FNSKU. Apply it to the bundle packaging, not individual items inside.
5. Wrong box size for the SKU
What Amazon wants: Cartons matching Amazon's case-pack specifications or within their size limits (max 25 inches on any side, max 50 lb for boxes).
What we see: oversized cartons with 60% empty space (dimensional weight penalties on shipping in); cartons over 50 lb (rejected entirely at receiving); loose items with excessive void fill (flagged as "improperly packed").
Fix: Pick a carton that's approximately 85% full when packed. Use void fill only to stabilize, not to fill void. Weigh every carton — if it's over 50 lb, split it.
6. Shipment plan mismatches
What Amazon wants: The FBA shipment plan you create in Seller Central needs to match the physical cartons exactly — item counts, SKU mix, and carton count.
What we see: sellers creating a plan for 500 units, shipping 480 because they miscounted, and eating the reconciliation hassle for months.
Fix: Physical count first, shipment plan second. If you're using a 3PL for prep, make them responsible for the count (at Shipprep, we scan every unit at receipt and generate the shipment plan based on actual physical inventory).
7. Missing or wrong PO numbers on cartons
What Amazon wants: Shipment ID, carton-of-carton-count, and (for some warehouses) PO reference on the outside of each carton.
What we see: cartons with no external labels at all, handwritten carton-of-count that's been smudged, wrong shipment IDs from a canceled shipment plan.
Fix: Printed carton labels only. One shipment ID per physical carton. If a shipment plan gets canceled and re-created, print fresh labels — don't cross out the old one.
The meta-lesson
Amazon's inbound process is automated. Their scanners expect specific formats. Anything outside those formats slows things down for the receiving team, and their default response to friction is "reject and return to sender."
The seven fixes above cover ~80% of rejection reasons we see. The remaining 20% is product-specific stuff (hazmat classification, category-specific requirements for jewelry or supplements, etc.) that varies per SKU.
If you're getting rejections or reduced receive rates on your FBA shipments, the likely culprit is on this list. If you want to skip learning it the hard way, outsource prep to someone who does it daily.
If you're running into FBA rejections and want a second pair of eyes on your prep process, send us a photo of your last shipment (labels visible). We'll flag anything we'd fix before it goes to Amazon — no obligation, just a quick review.