I don't know if this is helpful, i found it with Dr. Google
https://bbs.archlinux.org/viewtopic.php?id=225717
If this issue is libsoup related - Maybe the issue was already fixed and
is now "reimplemented"
My System says:
Package: libsoup2.4-1
Versions:
2.60.1-1
Public bug reported:
Hi all,
I installed today a fresh ubuntu 17.10. including Evolution and
Evolution-ews.
In Evolution I added my office 356 account.
Emails working like normal.
But I cannot open my office 356 Calendar.
Unable to connect to “Kalender”: Backend factory for source
