Product qty need to be more than 0

Such error appears, when, in the Price, Quantity and Format Policy, you set settings to take QTY from Product QTY and it is 0. Or the QTY is set to be taken from custom attribute and this attribute has empty value or 0 as value.

Please, follow this link to read about Price, Quantity and Format Policy settings or for M2E Pro Magento v2.x

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