If there is a problem with importing your order into the SPOD app, this will be clearly highlighted to you on the dashboard of the SPOD app.
Please see the screenshot below for an example of what this looks like.
By clicking the "See Orders In Shopify" button, you will taken to the order in Shopify's backend. Here, you are able to fix any issues wit the order. The issue is normally with the shipping address.
You will also find the error message in the Order Detail page. By clicking the "See Order In Shopify", you will be taken the order page in the Shopify backend to fix any issues with the order.