CalDavSynchronizer - single Items not synchronized

Dear Community,
my setup is a single-server instance of nextcloud v18.06 with calendar app v2.0.3 and contact app v3.3.0.
The source of my data is an outlook instance (v2016) in my office with caldavsyncronizer v3.8.2.0, which synchronizes my calendars, contacts and todo items with my nextcloud instance.

Basically the sync works, but sometimes single items are left out - i.e. 80% of the birthday items are synced, the rest doesn’t show up on nextcloud, or some contacts are left out of the sync.

Unfortunately the forum search brought no help - so has anybody encounterd this weird behaviour and has a solution - or a helping idea - for this problem ?

Thanks a lot !

Yours
Wolfgang

The server stores the data but isn’t responsible for the correct synchrinization, therefore I would recommend to check the Outlook CalDav Synchronizer website for any help. In their support section e.g. you will find information how to debug such problems etc.