ShipMagic uses online services to help pre-populate and verify your Ship To address while you are entering it. While this can be "magically" time saving, it also can result in problems if the address you are entering can't be validated.
There are two ways ShipMagic handles address issues. The first one can happen if the address entered appears invalid. In this case you can't go any further. If this occurs, try removing any entries in the Apt/Suite space. This will allow ShipMagic to try to validate the street address. Address validation issues are often related to the Apt/Suite field since there are many different ways to enter this information.
If the address will validate without the Apt/Suite field entered, then you know you at least have the correct street address. If you are very sure about the information you were entering in the Apt/Suite field, you can add it to the end of the Address information and leave the Apt./Suite field blank. When you use this method, you should advance to the next step. You will likely see a warning that your address may be wrong, and the package may be returned. Now it is up to you. If you know the address is correct, you can continue with your label purchase. If you are unsure of the address, you should contact the recipient to verify it, prior to purchasing a label.