I am using the Synology CARDDAV server for quite a long time. Without updating app or server, the sync failed after editing a single contact.
The sync of this contact failed: https://da.gd/vizp
It occurs when I enter only a company name and no name (no first name, no surname).
I remember that I had contacts like that before and it worked. It’s a typical use case when you want to store the number of a company where you do not have a specific contact.
Why does the log say “Calendar (!!!) data had unfixable problems”?
Looks, like it is related or similar to: https://forums.bitfire.at/topic/782/synchronization-stuck-if-vcard-do-not-contain-n-fn-field-403-forbidden-synology/10 . But as my server states “Calendar”, I don’t know it is the same topic.
Of course, I cannot clearly tell if this is a server or client issue.
What shall I try out next?