Icloud-for-linux - applications fail to start

Hello,

I am running Ubuntu 16.04 and have just installed “icloud-for-linux” using Snap,

sudo snap install icloud-for-linux

The installation seems to have gone without any problem,

$ ls /snap/bin
icloud-for-linux.calendar icloud-for-linux.notes
icloud-for-linux.contacts icloud-for-linux.numbers
icloud-for-linux.drive icloud-for-linux.pages
icloud-for-linux.find-my-friends icloud-for-linux.photos
icloud-for-linux.find-my-iphone icloud-for-linux.reminders
icloud-for-linux.keynote icloud-notes-linux-client
icloud-for-linux.mail

But when I try to run one of the applications - icloud-for-linux.notes, say - I get the following error message,

$ icloud-for-linux.notes
realpath: ‘’: No such file or directory
realpath: ‘’: No such file or directory
realpath: ‘’: No such file or directory
realpath: ‘’: No such file or directory
realpath: ‘’: No such file or directory
realpath: ‘’: No such file or directory
realpath: ‘’: No such file or directory
realpath: ‘’: No such file or directory
qt.qpa.screen: QXcbConnection: Could not connect to display :0
Could not connect to any X display.

Can someone suggest what I need to do to have the icloud-for-linux applications working?

Thank you in advance.