Site referrals "Full List" blank!

[mike123]

* Plesk version 12.0.18

In the AWStats, under "Connect to site from", there are four lines:
1- Direct address / Bookmark / Link in email...
2- Links from an Internet Search Engine - Full list
3- Links from an external page (other web sites except search engines) - Full list
4- Unknown Origin

Only numbers 2 and 3 have a link beside them for the "Full list", and even then when I open the full list of either, there is nothing there!

My question is, how to fix that issue to show content on the full lists?

Thanks