Amazon FBA shipment rejections and warehouse errors are among the most frustrating and costly problems a wholesale seller can face. A rejected box means your stock cannot be received — it either sits at the fulfilment centre dock awaiting correction instructions or gets returned to you at your cost with no sale made and your capital tied up in transit. A warehouse error — where Amazon receives fewer units than you sent or assigns received units to the wrong account — triggers an investigation process that can take weeks to resolve and during which your inventory is inaccessible. Both problems are almost entirely preventable when you understand the specific causes and build the right checks into your preparation process before every shipment leaves your hands.

We are Brandhunterz Ltd — a UK registered wholesale sourcing company (Company No: 15342697) — and in this complete guide we cover every major cause of FBA shipment rejections and warehouse errors — what triggers them what Amazon does in response and the exact preparation steps that eliminate each problem before your shipment ever leaves your location.

The Difference Between a Rejection and a Warehouse Error

Before covering the individual causes it is important to understand the distinction between these two types of problems — because they occur at different points in the fulfilment process and have different consequences and resolution paths:

Problem Type	When It Occurs	Immediate Consequence	Resolution Timeline
Shipment Rejection	At the receiving dock — before units are processed	Box refused — returned to sender or held pending seller instruction	Days to weeks — return shipping plus repack and resend
Warehouse Error	During or after receiving — once units are partially or fully processed	Discrepancy flagged — units held or short-received — investigation opened	Weeks to months — investigation required with documentation

Rejection Cause 1 — Missing or Unreadable FNSKU Labels

The most common cause of unit-level rejection at Amazon FBA is a missing unreadable or incorrectly applied FNSKU label. Units that arrive at the fulfilment centre without a scannable FNSKU on their outermost surface cannot be received into your inventory — Amazon has no way to identify who sent the product or which seller account to assign it to. These units are either held for relabelling at your cost or returned to the sender.

FNSKU Label Failure	Cause	Prevention
Label missing entirely	Unit packed before labelling — labelling step skipped in error	Count labelled units against plan quantity before boxing — never pack unlabelled units
Label not scannable — smudged or blurred print	Inkjet printer used — toner low — print settings scaled rather than 100 percent	Use laser or thermal printer — scan-test first label before bulk printing — always print at 100 percent scale
Label peeled off in transit	Applied to curved surface — poor adhesion — label edges lifting at time of application	Apply only to flat surfaces — press firmly from centre outward — check edges fully adhered
Original barcode not covered — scan conflict	FNSKU applied beside rather than over original barcode — original barcode still scannable	Position FNSKU directly over original barcode — cover completely — use opaque sticker if barcode is larger than FNSKU
Label applied inside poly bag or under wrap	Unit labelled before bagging — FNSKU inside bag or under bubble wrap	Always apply FNSKU to outermost surface — label goes on the poly bag exterior not the product inside

Rejection Cause 2 — Box Over Weight or Size Limit

Boxes that exceed Amazon’s 50kg gross weight limit or 63.5cm maximum dimension on any single side are refused at the fulfilment centre receiving dock. There are no exceptions and no grace margins — a box that is 51kg or 64cm in any direction is refused and returned. This is one of the most preventable rejection causes because it requires only a scale and a tape measure to confirm before dispatch.

Limit Exceeded	Most Common Cause	Prevention
Over 50kg gross weight	Dense products — heavy stock — too many units per box — void fill not accounted for in weight estimate	Weigh every fully packed sealed box before labelling — split into two boxes if over limit
Over 63.5cm any side	Using large supplier or manufacturer boxes without checking dimensions — long or flat products	Measure all three sides of every box before packing — use appropriately sized shipping boxes

Rejection Cause 3 — Expired Products or Insufficient Shelf Life

For food grocery supplements and health products Amazon requires a minimum of 90 days remaining shelf life from the date the shipment arrives at the fulfilment centre. Products with less than 90 days are refused and either returned to the seller or disposed of. This rejection is particularly damaging because it typically affects an entire category of units in the shipment — not just one or two — and the cost of return shipping on a large quantity of expired food or supplement stock is significant.

Expiry Issue	Prevention
Product expires within 90 days of FBA arrival	Check every unit’s expiry date when stock arrives from supplier — account for transit time when calculating remaining shelf life
Expiry date not visible or not in correct format	Apply a supplementary expiry date sticker in MM-YYYY format — confirm it is visible on the outermost surface before boxing
Supplier sends batch with short remaining shelf life	Specify minimum shelf life requirement on every purchase order — reject and return any non-compliant batch before sending to FBA

Rejection Cause 4 — Non-Compliant Unit Packaging

Products that require additional prep — poly bagging suffocation warning labels bubble wrapping or set labelling — and arrive at the fulfilment centre without that prep will be refused at unit level. Amazon identifies prep requirements for specific product types during the shipment plan creation process and holds sellers accountable for meeting them. Units that arrive needing prep they do not have will either be returned or held for Amazon’s prep service at the seller’s expense.

Missing Prep Type	Products Affected	Prevention
Missing poly bag	Loose or powder products — multi-part sets — fabric items without retail packaging	Check prep requirements in shipment plan — poly bag every required unit before boxing
Missing suffocation warning on poly bag	Any poly bag with opening over 12.7cm	Use pre-printed poly bags with suffocation warning — or apply warning sticker to every bag
Missing bubble wrap on fragile units	Glass ceramic delicate electronics	Wrap all fragile units individually — minimum 2 inches bubble wrap on all sides — confirmed before boxing
Missing Sold as Set label on bundle	Any multi-component product sold as one unit	Apply Sold as Set — Do Not Separate label to outer packaging of every bundle before shipping

Rejection Cause 5 — Shipment Sent to Wrong Fulfilment Centre

Amazon assigns a specific fulfilment centre to receive each shipment based on your ship from address product type and its network capacity at the time the plan is created. If your boxes are delivered to a different fulfilment centre than the one assigned — whether because you changed the delivery address instructed a courier to use a different destination or your courier misrouted the shipment — Amazon will either redirect the boxes at your cost or refuse them entirely. Never change the destination of an FBA shipment after the plan has been confirmed.

Warehouse Error Cause 1 — Quantity Mismatch Between Plan and Box Contents

The most common cause of warehouse receiving errors is a discrepancy between the unit quantity declared in the shipment plan and the actual number of units found in the boxes at receiving. Amazon scans every unit it receives and reconciles the count against your declared quantity. Any difference — even a single unit — triggers a receiving discrepancy investigation that freezes the affected inventory and requires seller action to resolve.

Quantity Mismatch Cause	Prevention
Entered wrong quantity in shipment plan	Count stock before opening Seller Central — enter the exact counted quantity — not an estimated figure
Supplier delivered fewer units than invoiced	Count every unit on arrival from supplier — match against invoice before creating shipment plan
Unit damaged and removed but plan not updated	Remove damaged units from count before entering plan quantity — never pad or round the figure
Unit lost during packing — fell behind furniture or under desk	Count labelled units immediately before boxing — count again after all boxes sealed and weighed

Warehouse Error Cause 2 — Missing or Incorrect Box Content Information

When box content information is not entered in Seller Central before dispatch Amazon must manually scan every unit in every box to determine what is inside them. This process is slow generates a per-unit compliance fee and significantly increases the risk of receiving errors because manual scanning at speed is less accurate than system-guided receiving. Always enter box content information for every box in every shipment without exception — it is one of the highest-impact steps in the entire shipment preparation process.

Box Content Error	Consequence	Prevention
No box content entered — skipped	Manual scan compliance fee per unit — increased error risk — delay in going live	Complete box content entry for every box before confirming shipment — never skip
Declared quantity does not match actual box contents	Receiving discrepancy — investigation — potential charge for unresolved discrepancy	Enter box content quantities only after physically packing and counting each box
Wrong ASIN entered for box contents	Units received against wrong ASIN — misattributed inventory — difficult to correct post-receiving	Verify ASIN from Seller Central listing — do not type from memory — copy from the shipment plan

Warehouse Error Cause 3 — Box Label Mix-Up

Each box in your shipment has a unique numbered box label — Box 1 Box 2 Box 3 and so on. Each label is associated in Amazon’s system with the specific contents declared for that numbered box. When the wrong label is applied to the wrong box — Box 2’s label on Box 1 and Box 1’s label on Box 2 — the declared contents do not match the actual contents of the scanned box. Amazon flags this as a receiving discrepancy even though no units are actually missing — because its system cannot reconcile what was declared against what it received under that box label.

Box Label Error	Prevention
Wrong box label applied to wrong box	Print and apply box labels one at a time — apply Box 1 label immediately to Box 1 before printing Box 2 — never batch print all labels and apply separately
Box label applied to wrong side — obscured or damaged	Apply each box label to the largest flat face — away from seams — confirm it lies flat and reads cleanly before sealing the box in the stack
Two box labels on one box — duplicate applied in error	Check each box has exactly one box label before stacking — remove any duplicate immediately and replace with single correct label

How to Resolve a Receiving Discrepancy When One Occurs

Even with the best preparation process in place receiving discrepancies do occasionally occur — particularly on high-volume shipments or when working with new products. When a discrepancy appears in your Seller Central shipment status here is the resolution process to follow:

The Complete Pre-Shipment Rejection and Error Prevention Checklist

Pre-Shipment Check	Prevents	Done
Scan-test FNSKU label sample before bulk application	Unreadable label rejection at unit level	☐
Count labelled units before boxing — match against plan quantity	Quantity mismatch warehouse error	☐
Confirm FNSKU applied on outermost surface — not inside bag or wrap	FNSKU unreadable at receiving — unit held	☐
Check expiry dates on all applicable units — minimum 90 days confirmed	Expired product rejection	☐
Poly bag suffocation warning and set labels applied where required	Non-compliant packaging rejection	☐
Every box weighed — under 50kg confirmed — every box measured — under 63.5cm confirmed	Box rejection at receiving dock	☐
Box content entered for every box — ASIN quantity and dimensions	Box content compliance fee and warehouse error	☐
Correct numbered box label applied to correct numbered box	Box label mix-up warehouse error	☐
Courier booked to correct assigned fulfilment centre address	Wrong destination rejection	☐
Photographs taken of labelled boxes and box labels before collection	Evidence gap if discrepancy investigation required	☐
All checks passed — shipment ready for collection		✅ Go

Conclusion — Prevention Is Always Faster and Cheaper Than Resolution

Every rejection and every warehouse error costs more to resolve than it would have cost to prevent. Return shipping on a rejected box typically exceeds the original inbound courier cost. A warehouse discrepancy investigation can take weeks and freeze your inventory at a time when you need it live and generating sales. The pre-shipment checklist in this guide takes under ten minutes to complete per shipment and eliminates the vast majority of rejection and error causes before your boxes ever leave your location. Make it a non-negotiable part of every single shipment without exception.

Find your next wholesale brand through our Brands Directory. Research every product with Keepa. Confirm every margin with AMZScout. And protect every shipment with the prevention checklist in this guide.