Invalid size system value

size_system must be one of: AU, DE, FR, UK, US. Other values default to the target country system or are rejected.

Microsoft Merchant Center's product schema has format and value rules per attribute. This issue is typically: missing a required attribute for the category, an invalid enum value (e.g., 'XL' submitted where 'M, L, XL' is the valid set), out-of-range numbers, or attributes that conflict across the feed.

1. Look up the affected attribute in Microsoft Merchant Center's product data spec.
2. Check whether the attribute is REQUIRED vs RECOMMENDED for your product category.
3. For enum-style attributes (gender, age_group, condition), use ONLY documented values exactly (case-sensitive).
4. For free-text attributes, stay within the character limit and avoid promotional language.
5. Re-submit and check the next processing cycle.

• Submitting case-mismatched enum values — most channels require exact case match
• Mixing attribute formats across products in the same feed — keep consistent