Found Solution (combined) for OctoPi 0.18.0 with TouchUI and not connecting to [::1]

I've been looking for hours for a solution to my problem, the chromium browser & touchUI not connecting properly and getting the TouchUI error "Cannot connect".

Part of the solution is in the post @foosel made here:

Action:
~/oprint/bin/octoprint config set --bool server.allowFraming true
sudo service octoprint restart
sudo service touchui restart

That solves the framing problem, but not the connection problem. What I've found to be working is:

action:
sudo nano etc/default/touchui

then edit the line:

TOUCHUI_PORT="8888"

and change it to:

TOUCHUI_PORT="80"

This may be a "hack" but at least I get the OctoPi interface to work on my Raspberry Pi 4B 8Gb.