5 Critical FBA Prep Mistakes That Will Get Your 2026 Shipments Rejected
As of January 1, 2026, Amazon no longer handles prep or labeling on your behalf. Every unit must be fully compliant before it touches the fulfillment center conveyor belt. A unit that is not can be refused at receiving, logged as a defect on your Inbound Performance dashboard, charged an unplanned prep service fee, and, on shipments created after January 1, 2026, left without reimbursement if it is damaged or lost.
Repeated violations put the account at risk of suspension, restricted selling privileges and loss of optimized placement options, and boxes without an FBA box ID label can get shipments blocked. Here are the five most common FBA prep mistakes causing rejections, and exactly how to eliminate each one.
Mistake 1: Unmasked Manufacturer Barcodes
Every FBA unit must display one scannable item barcode, the only exception being a Transparency code, which must never be covered. Visible manufacturer barcodes (UPC, EAN, ISBN) alongside FNSKU labels trigger unscannable flags. After March 31, 2026, resellers must use FNSKU labels exclusively, no manufacturer barcodes allowed.
The fix: Apply FNSKU labels over every existing barcode with complete coverage. Verify with a handheld scanner before sealing.
Mistake 2: Missing Safety Labels on Heavy Cartons
A box can only exceed 50 lb when it holds a single oversize unit, and those boxes require a "Team Lift" label on the top and sides, or a "Mech Lift" label above 100 lb. A carton between 33 lb and 50 lb needs no lift label at all.
The fix: Weigh every carton, apply Team Lift labels to the top and sides of any box over 50 lb, use local language labels for destination country.
Mistake 3: Poly Bag Thickness Violations and Missing Suffocation Warnings
Poly bags must be at least 1.5 mil thick, transparent or carrying the item barcode on the outside, fully sealed with tape or an adhesive strip, and protruding no more than three inches past the product. Bags with a 5" or larger opening require a suffocation warning sized by the bag, 24 point at 60 inches of length plus width or more, down to 10 point under 29 inches, visible after sealing.
The fix: Source pre-printed 1.5 mil bags with warnings. Inspect samples from every batch and confirm visibility after sealing.
24 to 36h prep. 35-hour end-to-end guarantee or the prep is free. Net-30 terms. From 50 units to full truckloads.
Mistake 4: Non-Scannable Labels on Curved Surfaces
Labels on curves, seams, folds, or glossy stock fail automated scanners. Amazon also refuses damaged or photocopied labels, and calls for printing at 300 DPI or greater.
The fix: Place FNSKU on flat smooth surfaces only. Use black ink on white, non-reflective labels with removable adhesive. Amazon optimizes its label tools for thermal printers, accepts laser printers, rules out inkjet, and calls for 300 DPI or greater on any printer. Test scannability through outer packaging.
Mistake 5: Exceeding Box Dimension and Weight Limits
Maximum 50 lb per box, 36" on the longest side and 25" on the other two. No taped-together boxes, damaged cartons, or banned dunnage (peanuts, shredded paper).
The fix: Weigh/measure every carton. Use new corrugated boxes. Approved dunnage only: bubble wrap, air pillows, polyethylene foam.
Pre-Ship Checklist
- One scannable barcode per unit, manufacturer barcodes fully covered
- FNSKU on flat surface, scannable through packaging, 300+ DPI
- Poly bags 1.5 mil minimum, adhesive sealed, suffocation warning visible
- Team Lift labels only on boxes over 50 lb, which are allowed only when the box holds a single oversize unit
- No box exceeds 50 lb, 36" on the longest side or 25" on the other two
- New corrugated boxes, approved dunnage only
- "Sold as Set" stickers on bundles
- Final scan test on sample cartons
The Cost of Getting It Wrong
The inbound defect fee is not a prep penalty. That fee, $0.32 to $1.74 per unit standard and $1.38 to $5.72 bulky, covers shipments that are misrouted, deleted or abandoned after approval, or incomplete against the plan. Prep mistakes cost you in other ways: refused units, defects logged against your Inbound Performance, possible unplanned prep service fees, and no reimbursement on unprepped units that get damaged or lost. Rejected inventory kills in-stock rates and takes you out of the Featured Offer entirely while the ASIN is out of stock. These five mistakes cause most inbound failures, eliminate them to clear receiving cleanly.
