Your code in the original post say real='Privacy Guard', but the lwp-request headers ask for realm='Maintenance Guard'.

So the correct realm on your code would be 'Maintenance Guard', i guess.

Also make sure you get upper/lowercase of all authentication fields correct (username, password, realm).

I can't really test your setup. For that, i would need username+password, but i will never ask for that unless you are a paying customer of my employer due to all sorts of legal and insurance reasons. So do not post the authentication data. The only thing i can advise you to do is to check if your authentication data is correct by using your browser to log in.