[Evolution] evolution 3.19.90 : caldav timeouts?

[Kristian Rink <kawazu428 gmail com>]

Folks;

using Evolution 3.19.90 on an Ubuntu 16.04 system, I cannot get CalDAV
calendars or task lists to work anymore as they all seem to run into a
"connection timeout". Accounts were manually set up in evolution,
leaving out GNOME online accounts here.

Any idea how to figure out what's happening here?
TIA,
Kristian