Hi,
I managed to set up the syncing of my Contacts with my iCloud account (after I found out that I need an App password!!). At least now it´s not giving me the “Server says unauthorized” message anymore.
But the syncing only seems to be working one way. I added a contact named Testkontakt in eM Client and it showed up on my iPhone almost immediately.
But a contact Testkontakt1 that I´ve added on my iPhone doesn´t show up in my eM Client contacts list. 
Any idea why this is not working?
Herbert