Handle MSI problems

Order Split distinguishes two situations:

MSI is unavailable

This applies when source routing is enabled in Order Split but the required Magento inventory modules are not available. Behavior When MSI Is Disabled can:

• continue with vendor-only groups
• submit one original order
• block checkout

MSI is available but no source is resolved

This applies when source selection fails, uses several sources for one item, or does not cover the complete requested quantity. Behavior When Source Cannot Be Determined controls the result independently.

Diagnostic checklist

1. Confirm the website is assigned to the intended stock.
2. Check that source items are enabled and have sufficient salable quantity.
3. Confirm the configured source-selection algorithm is available.
4. Test the exact SKU, quantity and destination from the cart.
5. For composite products, check the child SKUs sent to inventory selection.

Use vendor-only fallback when warehouse separation is optional. Use blocking behavior when sending a group to the wrong fulfilment location would be worse than stopping checkout.