Item ... requires delivery within ... calendar days, but delivery will take ... in transit. Box would ship on ... and be delivered on ...

This is one of the error message that is displayed on the view packing solution screen. It can be remedied.

Let's say we are shipping lobster that requires 1 day delivery.  In the checkout we receive the message "Unable to determine any shipping estimates".

If we click on the view packing solution link another tab will display in the browser with more information on why each shipping method did not estimate like the example below.

Notice that the PeriShip methods are not estimating because item 1702 requires 1 calendar day delivery and the estimate is coming back with the maximum of 365. To troubleshoot this we need to look at how the method is configured to estimate delivery.  Navigate to the estimated delivery tab of the method:

Once you are on this page make sure the estimate type is set to real-time using information provided by the shipper if you are using FedEx or PeriShip.

For any other carrier you will have to use one of the other four options to estimate how long the carrier takes to ship things. For example UPS Next Day Air is going to require one business day to arrive whereas USPS Priority Mail will be one to three business days.  Click Save when finished.