This is a website which consists of Iranian traditional songs. we have to log
in this site if we want to search within the archives. 
I want to download the whole website and I want the MP3 files of this website.

When I enter the URL in HTTrack app and continue I encounter an error in log
files which is: 
HTTrack has detected that the current mirror is empty. ...

Can somebody help me out through this issue. What steps and justifications
should I follow?
Thank you ...