Hi I just joined the forum after a clean install of suitecrm 7.10.4 on a clean Ubuntu server 17.10 system
Everything was working very nice but the iCal link for displaying the the calendar in an external program or in browser needs username and password.
Long story short, I got things working by replacing email in the iCal-link to user_name
You can read the whole bug description I filed:
I hope I saved somebody the time it took me to figure this out :S