A user is configuring a server OS.

According to the CompTIA Tech+ Study Guide:

“Changing Default Usernames and Passwords — The first thing a potential hacker will try to use is the default username or password for a device. Always change them.”

It also emphasizes:

“Enabling passwords and changing default usernames and passwords are essential password management best practices.”

Therefore, the correct action after server setup is to change the default usernames and passwords to secure the system.

Verified Reference:

Chapter 11: Security Best Practices — “Managing Passwords” (pp. 594–595).