When a candidate has multiple email addresses, NIXZ automatically chooses the most suitable address for sending.
If the primary email address was retrieved by NIXZ, this is determined based on the email type and the quality of the data. In that process, a personal email address is usually preferred over a business email address. NIXZ also checks the quality score and whether the email address has been verified.
This way, NIXZ prefers the address with the highest chance that the message will actually arrive and reach the candidate personally.