Since you are not able to run as sudo, it will not be able to bind the traditional telnet port (23) without some other configuration changes to your OS. Linux restricts users from using ports less than 1024 without some configuration or tricks.
Hello depending on what distro he is running her could also install authbind
An alternative may be to use authbind.
Install authbind using your favorite package manager for your Linux Distribution.
Configure it to grant access to the relevant ports, e.g. to allow 80, 21, 23,25, 110, etc 443 from all users and groups:
sudo touch /etc/authbind/byport/80
sudo touch /etc/authbind/byport/443
and so forth for all ports you are using below 1025 ...
sudo chmod 777 /etc/authbind/byport/80
sudo chmod 777 /etc/authbind/byport/443
So on and so on.
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