Answer:
Configure a safe sender.
Step-by-step explanation:
Spam is a computer term that designates unwanted messages in an email, as well as advertising messages on websites. The main characteristic of these messages is that they do not respond to any previous action on the part of the receiver, such as a conversation with the sender or an advertisement that arises from search engine algorithms, but is sent randomly by an anonymous sender with objectives that are not entirely clear or legitimate.
Therefore, if Walt wishes that his colleague's messages are not classified as spam, he must categorize this person as a safe sender within his email box.