Amazon Error Messages

Amazon returns an error code or message when it rejects something PrepBusiness sends on your behalf. Most of these are resolved on Amazon's side, in Seller Central, rather than in PrepBusiness. This guide lists the errors we see most often, what causes each one, and what to do about it.

Errors are grouped by where they come up. Use your browser's find function to search for the exact wording Amazon returned.

Listing and catalog errors

These happen when the item in PrepBusiness and the listing on Amazon do not agree, or when the Amazon listing is missing information.

MISSING_DIMENSIONS

The product is missing dimensions for FBA. Add the dimensions to the item in PrepBusiness, then push them to the Amazon listing.

Go to Inventory and open the item.
Select the Dimensions tab.
Enter the length, width, height, and weight, then click Save Dimensions.
Click Sync to Amazon Listing.
Tick the listings you want to update, then click Update.

amazon-error-messages-missing-dimensions-sync-20260805-140300.png

If the dimension fields are greyed out, the card is set to Locked. Click the x on the Locked badge in the top right of the card to unlock it. Only a staff user on the account can unlock dimensions; client users cannot.

If nothing happens when you click Sync to Amazon Listing, the item is not linked to an Amazon listing yet. Link it first, see Linking Items to Listings.

Note: Amazon can take 15-30 minutes to push updates to their FBA system. Wait and try again if the error persists.

UNKNOWN_SKU, or "The following MSKUs are not valid"

Amazon does not recognize the SKU as a valid FBA listing. This almost always means the product is not set up as Fulfilled by Amazon in Seller Central.

The seller needs to create the SKU as an FBA listing in Seller Central. Once the listing is active, it will sync to PrepBusiness and can be used in outbound shipments. If the listing is already active and you still see this error, check that the SKU in PrepBusiness matches the seller SKU on Amazon exactly, including case.

NOT_IN_PRODUCT_CATALOG

Amazon cannot find the product in its catalog for the marketplace you are shipping to. This usually means the listing exists in a different marketplace, or was created very recently and has not finished propagating.

Confirm in Seller Central that an active listing exists in the destination marketplace. If it does and the error persists after an hour, contact Seller Central Support with the SKU and ASIN.

NO_EXTERNAL_IDENTIFIER_FOR_EXISTING_MAP

The product is missing a UPC or EAN on Seller Central. Add the identifier to the listing in Seller Central.

EXTERNAL_ID_MAPS_MULTIPLE_IAIDS

The item has a new FNSKU and cannot be posted under the existing one. Update the FNSKU on the item in PrepBusiness to match the current FNSKU on Amazon. You can find the FNSKU on the item's Identifiers tab.

EXP_DATED_ITEM_HAS_EXISTING_STICKERLESS_MAP

The SKU is marked as a commingled (stickerless) product but should not be, because it is an expiry-dated item. Create a new listing for the same ASIN with a different SKU, and make sure it is set to labeled rather than commingled.

INVALID_MSKU_REMAP

The ASIN on the item in PrepBusiness does not match the ASIN on the Amazon listing. Correct the ASIN in PrepBusiness:

Go to Inventory and open the item.
Select the Identifiers tab.
Delete the incorrect ASIN, then add the correct one.

Identifiers cannot be edited in place, so you delete the wrong value and add the right one. The ASIN type only appears in the identifier dropdown for users with the Owner role. If you do not see ASIN as an option, ask an Owner on the account to make the change.

Item Not Synced With Channel

There is no link between the inventory item in PrepBusiness and the listing on Amazon. Link them rather than creating anything new:

Go to Inventory and open the item.
Select the Listings tab.
Choose the matching Amazon listing and link it.

See Linking Items to Listings for the full process, including what to do when no matching listing appears.

"The attribute name is invalid. Please remove name and re-submit."

Amazon rejected one of the attributes PrepBusiness sent for this listing, usually because the product type does not accept that attribute. The listing cannot be updated from PrepBusiness in this case. Update the attribute directly on the listing in Seller Central.

Incorrect PrepInstruction Provided, and prepOwner errors

Amazon returns these when the prep or labeling owner on the shipment does not match what the listing requires. The message names the SKU, for example:

ERROR: SKU does not require prepOwner but SELLER was assigned. Accepted values: NONE.
ERROR: SKU requires prepOwner but NONE was assigned. Accepted values: AMAZON, SELLER.

Amazon decides per SKU whether the seller or Amazon owns prep and labeling, and it will reject a shipment that disagrees. Check the item's prep guidance in Seller Central and set the prep and labeling owner to match, then resubmit the shipment.

Hazmat, restricted, and stranded items

ITEM_WITH_NO_VALID_FC

The item has no eligible Fulfillment Center because it is classified as hazmat. You cannot send it to FBA.

ITEM_UNDER_HAZMAT_REVIEW

The product is under review by Amazon as a potential hazardous material. You cannot send it until the review completes. Reviews are handled by Seller Central Support.

"No fulfillment centers are currently available to receive the total quantity of dangerous goods units in this shipment"

Amazon cannot accept that quantity of dangerous goods or hazmat units at any fulfillment center right now. This is usually a temporary capacity limit rather than a problem with the product. Trying again later, or with a smaller quantity, often works.

PrepBusiness will show the specific SKU or FNSKU that triggered the error where Amazon includes it in the response.

FIOS_NO_PATHS_TO_CUSTOMER

There are no eligible fulfillment centers in the destination country for the SKUs listed. Remove the SKUs named in the error and ship them separately, or contact Seller Central Support.

LTSF_RESTRICTION

Amazon has held this item too long and automatically removed it from the warehouse. You cannot send more of this item for a period, often around three months.

ITEM_STRANDED

Amazon marks inventory as stranded for a number of reasons. The most common are below. All of them are resolved in Seller Central, not in PrepBusiness.

Pricing error. Amazon judged the price too low or too high and suppressed the listing. Set a minimum and maximum price under Manage Inventory in Seller Central.
Restricted ASIN. Amazon has restricted sale of the ASIN, for example for intellectual property reasons, product quality, or required safety testing. Contact Seller Central Support.
Suspended listing. Often caused by missing required information such as images, bullet points, or age requirements, or by a high return rate. Contact Seller Central Support if the cause is not obvious.
Listing error. The inventory is not connected to an active ASIN, usually because the listing was deleted by accident. Relist the ASIN on Amazon.
Brand qualification required. The ASIN or brand needs prior approval. You may need approval from the brand or an invoice from an authorized distributor.
Expired product. A perishable item has passed its expiry date. The inventory needs to be removed from Amazon's warehouse.
Closing or deleting a listing. Deleting a listing right after selling out strands any returns or lost inventory that arrive later. Relist the ASIN to recover it.
Bulk upload template error. If the quantity column is populated in a bulk upload template, listings switch from Fulfilled by Amazon to Fulfilled by Merchant, which strands the inventory. Contact Seller Central Support.

Placement, packing, and transport errors

These come up while working through an outbound shipment plan. The plan steps are named rather than numbered in this guide, because the number of steps changes depending on whether you know your packing information in advance.

"Something went wrong with placement. Please regenerate the packing options"

This usually means one or more items in the shipment now needs a new approval, or has been gated by Amazon since the shipment was started.

Cancel the plan and create it again. The box contents you have already entered can be copied into the new plan.

"No transportation option for the selected mode is available"

Amazon returned no transportation options for the transport mode and placement you selected. There is more than one possible cause.

A common one is selecting Partnered LTL. The request reaches Amazon, but Amazon does not always offer a partnered LTL (pallet) carrier for a given shipment, and returns an empty list instead. Whether partnered LTL is offered varies by destination fulfillment center, pallet weight and dimensions, and the product, so the same shipment can return partnered small parcel options while returning none for partnered LTL.

If partnered LTL comes back empty:

Try a different placement option at the Placement Options step.
Go back to the transport mode step and select Non-Partnered LTL to arrange a carrier directly.
Check whether partnered LTL is offered for the shipment in Seller Central's own interface.

The error can also appear for other reasons, for example items that are hazmat or have no eligible fulfillment center, or boxes and pallets outside the selected carrier's size or weight limits.

"Requested transportation options do not have the same carrier as confirmed options"

When a plan contains multiple shipments using the same shipping mode, for example partnered LTL, all of those shipments must use the same carrier. Go back to the Transportation Options step and make sure the carrier matches across every shipment in the plan before confirming.

"Please accept the null terms and conditions in country: DE"

This can appear for European marketplaces. The example shows DE, but it applies to others such as UK and IT.

It means the Partnered Carrier Program terms and conditions have not been accepted for that marketplace. Accept them in Seller Central for the country shown, then retry the shipment.

It can also appear when the wrong carrier is selected, for example DHL instead of UPS, so check the carrier selection before assuming it is a terms problem.

If you would rather not use a partnered carrier at all, switch to a non-partnered shipment and arrange transport directly with your own carrier.

Error Code: 412

One or more boxes or pallets in the shipment exceed the size or weight limits allowed by the selected carrier. Check the box and pallet dimensions against the carrier's limits, or select a different transport mode.

"Invalid request during APS"

Amazon returned an unclear error while processing transport details. The usual causes are:

The box or pallet dimensions exceed what the carrier allows.
For LTL, the transport contact details are invalid. Check that the phone number for the shipping contact is valid.
The ship-from address is invalid. Check it in Seller Central.

"Request does not match the carton count on file"

Amazon's carton count for the shipment does not match what was submitted. This happens when box contents are changed after transport data has been submitted, and also because of a long-standing Amazon bug affecting shipments over 1,000 cartons.

You can still request an estimate. If the estimate returns an error, submit the carton and transport data again.

"Delivery window cannot be updated outside of the grace period"

Amazon's grace period for changing a delivery window has ended. A confirmed delivery window can only be changed up until the window's start date.

The shipment needs to proceed with the window already confirmed on Amazon. If a different window is genuinely required, note that Amazon does not allow delivery window options to be regenerated once the placement option is confirmed, so the plan may need to be cancelled and recreated.

"The transportation options could not be found", or "Could not find shipment"

The placement option this request refers to has been cancelled, so the process cannot continue against it. Wait a moment, then regenerate the placement options.

"You must include a valid ShipmentId"

The temporary ID assigned to a previewed shipment expires after 48 hours. Delete the shipment and create it again.

"Please Check the Shipment. Invalid Status Change. Shipment ID"

To close a shipment after requesting labels, use Mark As Closed in the shipment's Actions menu. Marking it as shipped instead causes this error.

Messages from PrepBusiness

These are not Amazon errors. They are safeguards in PrepBusiness that stop conflicting requests from running at the same time. Nothing has failed when you see one.

"Operation name already in progress", or "A name workflow is already running for this plan"

A request of that type is already running for the plan, and a second submission was blocked. This is usually caused by a double click, or by clicking a confirm button again after going back a step.

The exact wording varies by operation, for example "Operation ConfirmTransportationOptions already in progress", "Operation GeneratePlacementOptions already in progress", or "A confirm placement option workflow is already running for this plan".

You may see this for confirming transportation options, confirming a placement option, generating placement options, fetching shipment items, or fetching packing group items.

Wait a few seconds, check whether the plan has already moved forward, and retry once if it has not.

"Can't add same box to different shipment in same placement option"

A single box cannot be assigned to two shipments within the same placement option. Review the box contents and assign the box to one shipment only.

"You can't confirm transportation option before placement option"

The steps must be completed in order. Confirm the placement option first, then the transportation option.

"Cannot modify boxes after data is submitted. Reset submissions first."

Box contents are locked once packing information has been submitted to Amazon. Reset the submission before changing boxes.

Generic and temporary errors

"Something went wrong. Please try again later.", or "Sorry, something went wrong. Please try again, or refresh the page"

Amazon returned a generic server error with no detail. Retry the request. Amazon's own guidance for this error is that if it fails more than two or three times, you should cancel the inbound plan and create it again. The box contents you have already entered can be copied into the new plan. If a fresh plan hits the same error, report it to us so we can open a support ticket with Amazon.

"Unexpected Error Occurred 500", or "Server Error"

An HTTP 500 from Amazon usually clears on its own within 30 minutes to an hour. Check the Amazon SP-API status page. If retrying two or three times does not get past it, cancel the inbound plan and create it again. If it persists beyond an hour, contact us.

"Amazon's carrier service encountered an error. Please try again later."

Amazon's carrier service is temporarily unavailable. Retry the request shortly.

"Shipment ID not found. Please retry after a few seconds"

Amazon has not finished creating the shipment on their side. Wait a few seconds and retry.

Errors from Amazon's older shipment flow

PrepBusiness now uses Amazon's current inbound API for all shipment creation and transport. The errors below come from Amazon's older shipment flow and will not appear in PrepBusiness. They are kept here because you may still encounter them working directly in Seller Central.

AmazonContractNotSigned. The seller has not accepted Amazon's Partnered Carrier Program terms. Accept them in Seller Central.
CarrierContractNotSigned. The seller has not accepted the carrier's terms. Accept them in Seller Central.
CarrierInvalidForMarketplace. The carrier is not supported in the marketplace the shipment originates from.
CannotConfirmTransportContent. The shipment request is not eligible for confirmation, usually because it is already confirmed.
CannotEstimateTransportContent. The shipment request is not eligible for an estimate. Check that the ship-from address is in a marketplace eligible for the Partnered Carrier Program.
CannotVoidTransportContent. The shipment request has progressed too far to be voided.