i noticed there are few links at bottom of that page all leading to different
website
you can either download each website separately or include them all in tab
scan rules like this:
+intranet.tuhh.de/*
+www.service.tuhh.de/*
+stau.rz.tu-harburg.de/*
+e-learning.tu-harburg.de/*
+webmail.tu-harburg.de/*

also if some forum requires you to be logged in to be read in web browser,
then login in httrack too