The Universal Address Lookup field uses some subfield names that don't perfectly match their field names in the Import Tool which can be confusing when importing values to this field.
Form - Universal Address Subfield Names
Looking at the image above, we can see the subfield names displayed on the form.
Import Tool - Universal Address Subfield Names
Looking at the image above, we can see some of the subfield names (highlighted in yellow) displayed on the Import Tool are different than what are displayed on the form.
Form Subfield Name
Import Subfield Name
Address Line 1
Address Line 2
The table above can be used as a reference when importing data to the Universal Address Lookup field.