[Inf-IT DAVcl] InfCloud stopped working

Hi,

I've moved my DAViCal server to a new system (RPi4 w/ Raspbian). DAViCal now runs as a virtual https host under Nginx (the old system used Apache2).

Now InfCloud stopped working. It just displays red exclamation marks.

Oddly enough, none of the other DAViCal clients (vdirsyncer, android clients) experienced any problems, they all continued functioning without even blinking.

Are there any special settings necessary for DAViCal / InfCloud when using Nginx?

-- Johan