Overview

On February 13 2026 Amazon Seller Central began returning error code MYO0001 whenever a seller submits an order ID that does not follow the platform’s strict character rules. The message appears instantly, halting the request until the ID is corrected. Sellers who process orders manually or through bulk tools must understand the exact format requirements to avoid unnecessary delays.

Key Points

• Error trigger — MYO0001 appears the moment an order ID contains any character outside the allowed set, stopping the transaction before it reaches Amazon’s backend.
• Allowed characters — Only uppercase A‑Z, lowercase a‑z, digits 0‑9, hyphens (-), and underscores (_) are permitted; spaces, punctuation marks, and symbols such as #, @, or & cause the error.
• Typical offenders — Copy‑paste actions from emails, spreadsheets, or PDFs often introduce invisible whitespace, line‑break characters, or formatting symbols that the system flags as invalid.
• Immediate correction — The request must be resubmitted with a clean ID; Amazon does not queue or retry automatically.
• No health impact — MYO0001 is a validation issue only; it does not affect account standing, performance metrics, or eligibility for programs.
• Bulk risk — Sellers handling hundreds of IDs per day are most vulnerable because a single malformed entry can halt an entire batch upload.

How the Validation Works

1. Pattern check — When an order ID is entered, Amazon’s API runs a regular‑expression test that accepts only [A-Za-z0-9\-_]+.
   • Example: The ID FBA123-456_789 passes because it contains letters, numbers, a hyphen, and an underscore.
2. Character scan — The system scans each byte; the presence of a space ( ), a hash (#), or a non‑printing character like a carriage return (\r) triggers a failure.