Overview

Amazon displays error code MYO1003 when a seller tries to ship more units than the remaining quantity allowed in an existing FBA inbound plan. The issue appears during the “Send to Amazon” workflow and can halt the shipment confirmation step. Understanding why the error triggers and how to correct the quantity mismatch is essential for keeping inbound operations on schedule.

Key Points

• Error definition — MYO1003 is generated when the quantity entered exceeds the units still pending for a specific shipment plan.
• No health penalty — The code is a validation check, not a compliance violation; it does not affect account health or trigger fees.
• Live inventory counts — Amazon continuously updates the “remaining units” figure as boxes are received, so the number shown at plan creation can become outdated.
• Manual correction required — Sellers must review the current shipment status and adjust the entered quantity to align with Amazon’s remaining expectation.
• Multi‑box plans are high‑risk — Plans that involve several cartons or split shipments increase the chance of a stale quantity entry.
• Team coordination matters — If another staff member ships part of the plan without updating the central record, the next user may encounter MYO1003.

How the Error Happens

1. Create a shipment plan — Amazon allocates a fixed number of units to one or more fulfillment centers based on the seller’s inventory file.
2. Ship partial cartons — As the seller sends the first box, the system marks those units as “shipped” and reduces the outstanding count.
3. Refresh lag or miscommunication — The seller opens an old browser tab, or a colleague ships additional units without logging the change.
4. Enter a higher quantity — When the seller later attempts to confirm the next box, the entered quantity is larger than the updated “remaining” figure.
5. System blocks the entry — Amazon returns MYO1003 to prevent an over‑shipment that could create inventory imbalances at the fulfillment center.