Posted by Gnomad on Aug 18, 2017; 6:14am
URL: https://itus.accessinnov.com/Troubleshooting-inability-to-bring-up-admin-web-pages-tp1461p1463.html

The issue bringing up the admin interface turned out to be a corrupted uci config file preventing the web server starting up:  /etc/config/uhttpd
Possibly unrelated, but this might actually have been caused by problems introduced way back with the original 1.51 SP1 code in

/etc/itus/ituswebfilter.sh

You will find a couple of instances of this comment missing a leading # character:

Add blacklist to dnsmasq

My admin interface came back again after restoring an old /etc/config/uhttpd and running

sh /etc/itus/ituswebfilter.sh

The fix has been committed to the GitHub repo, along with a bunch of others I've collated from @roadrunnere42, @user8446 and @wisiwyg along the way.  Hope this helps anyone else with a similar issue.