Troubleshoot Flex Shipping

The carrier is missing from checkout

Check the carrier and method first:

1. Flex Shipping is enabled for the current website.
2. The method is active and within its start and end dates.
3. The method belongs to the current website or all websites.
4. At least one active method rule matches, if rules exist.
5. A rate matches the destination, postcode, weight, volume and calculation scope.

Use Validate Methods and then simulate the same quote under Sales > Flex Shipping > Audit.

A postcode does not match

Check whether a regex pattern is set. A pattern takes precedence over the From and To fields and must match the full postcode. Invalid or disallowed patterns do not match.

For ranges, confirm that From is not greater than To. Numeric postcodes are compared numerically; other values are compared as normalized uppercase text.

Package scope returns no method

Every package needs a matching rate row with Calculation Scope set to Per Package. One unmatched package removes the entire method.

Check the package summary for an unexpected weight or volume. Then review product attribute mappings, missing-value policy, packing mode and package limits.

The selected rate is not the expected row

List all rows that match the same country, postcode, metrics and date. Then review the method's conflict strategy:

• First Match also considers country specificity and priority.
• Cheapest compares calculated prices, not only the raw amount field.
• Priority then Cheapest ignores rows outside the best priority group.

The amount is lower when free shipping is involved

For a shipment-level Per Weight Unit rate, Magento's free-method weight is used for the price calculation. Package building and rate-band matching still use the physical shipment metrics.

Audit entries are missing

Confirm that Enable Audit Logging is set to Yes. The module writes audit entries after a method price is resolved, so rejected methods do not produce the same successful calculation record.

Also check Audit Retention (Days) and ensure Magento cron is running.

A rule appears to be ignored

Rules only decide whether their own method is applicable. They do not edit a rate price. Check the rule's active dates, priority and conditions against the quote's shipping address. If the method has rules, at least one active rule must match.