To resolve the state field is required error you can be confronted with while adding properties for .IT domains, follow the procedure below.
When adding properties for .IT domains you could be confronted with the error shown on the image below.
The error comes up because the contacthandle you're adding the properties to has no information submitted in the "State" field.
To resolve the issue, update the contacthandle your adding the properties by adding the State in which the contact is located.
Once you've updated the contact handle, go back and add the properties again and the error message will not appear.