If you see the error "A shipping service is not specified" despite having specified shipping services, it is likely no Ship To Locations have been selected. The problem can be resolved by following these steps:

1) Click Customize Grid

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2) Scroll to the end and tick "Ship To Locations"

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3) Scroll to the right of the Marketplace Listings grid and click Edit in the Ship To Locations column:

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4) Tick at least one location you are willing to ship to:

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