I can’t fulfill a Shopify order via the Smart Send Premium app because there is no receiver phone number in the order or there are not enough digits for the phone number?

To correct this issue, scroll to the top of the order in the Fulfillment section of our app and correct the phone number in the ‘Shipping Address’ section (the phone number must be exactly 10 digits with no spaces or dashes for domestic shipments).  

Also in the Shopify>Checkout section in your Shopify admin, go to the ‘Form Options’ section and tick the option for ‘Shipping Address Phone Number’ to ‘Required’ and save.  This should minimise these types of issues from occurring in future where no phone number is supplied (although the buyer could still enter less than 10 digits or enter spaces and dashes unfortunately).