Hard 120206 - Missing or invalid ship to StateProvinceCode [Solution]

When processing orders you might come across the "Hard 120206 - Missing or invalid ship to StateProvinceCode" error.

This error is shown when the State Code used in an order does not have a correct format.

Feel free to follow the step-by-step guide written below or the video guide, as you prefer:
 

To do so:

1. Find the order through any of the possible ways (after Import Orders, Batches, Order History, etc) as it applies to the case
 

2. Click the edit button of the order you wish to change

3. Change the State Code accordingly

4. Press Save to apply the changes

If the rest of the information in the order is correct, you will be able to process it.