What Can I Do If NetworkManager Cannot Be Started? (Error Message: Failed to restart NetworkManager.service: Unit NetworkManager.service is masked)

Symptom

The error message "Failed to restart NetworkManager.service: Unit NetworkManager.service is masked" is displayed when NetworkManager is started.

Possible Cause

The service unit is disabled, so NetworkManager cannot be started.

Solution

Run the following command to clear the mask status of the service unit:

systemctl unmask NetworkManager