Mac does not connect to the internet (picks up self-assigned IP address)

Problem

You Mac stops connecting to the internet.
When viewing the Network Control Panel, a 'Self-Assign' 169 address appears for the IP address.

Environment

Macintosh computer running Catalina (Mac OS 10.15) and above.
Pomona College owned Mac on campus.

Solution 1

Reboot your computer. Test.

Solution 2

Reset Network Settings:

Click the Apple icon (top-left corner) and select System Preferences.
In the System Preferences window, click on 'Network'.
Remove the Wi-Fi connection.
1. Select the Wi-Fi connection from the list of connections.
2. Click the minus icon (lower left corner).
3. Click 'Apply'.
NOTE:
- If the ethernet connection is also displaying a 169 address, do the same for it.
- Make sure that you have Wi-Fi login information for other networks you may use. You will need to re-enter it after the next step.
Recreate the Wi-Fi connection.
1. Click the plus icon (lower left corner).
2. Change the 'Interface:' option to Wi-Fi.
3. Click 'Create'.
4. Click 'Apply'
NOTE:
- repeat these steps to add back ethernet.

Reboot your computer. The network connection should now be restored.