Some address locator styles may require more than one table, such as US Streets with AltName. The Primary table usually requires a feature class, and an Alternate name table, which are in the same geodatabase. The fields for each table should be mapped to the fields in the reference data table, respectively.
Choose the field for each table specified in the address locator style from the correct reference table. For example, do not map a field for the Alternate name table from the primary street feature class.