Magento Item Export Error Message: 'Can't export an item which is not marked as a Magento item...'

Error on Item Export

Error Message: 'Can't export an item which is not marked as a Magento item. If this error happens again then please contact Celigo Support.'

Reason: The Magento Item checkbox on the custom tab is not checked.

Resolution:

Check the checkbox on the custom tab and then retry.