How to solve "User is not in sudoers file, incident reported"
sudo exclusively uses account names, not the user's full name. As a hint, account names don't contain spaces, so &quot;Syammala Naidu&quot; is not correct.
To find out a user's account name:

Open Terminal and run:
id -un



or, alternatively:

Open System Preferences.

Select Users &amp; Groups.

If necessary, click the lock on the bottom left corner of the window and type an administrator's name and password to unlock the preference pane.

Right-click the account and select Advanced Options....

Locate the Account name property:



Use that account name in /etc/sudoers. To edit the file, use visudo. For more information, check man visudo and man sudoers.