On-Premise Server Side Syn doesn't synchronize tasks and appointments created in Outlook into CRM

We are testing server side sync on-premise with CRM 2016. We are not using CRM Add-In for Outlook. Only server side sync with an exchange server. When we create a task or an appointment inside outlook under the mailbox of an existing user inside crm, we do not see them inside CRM. They are not synchronized into CRM. But the opposite will work, means when we create them in CRM, we can see them after a while in Outlook or OWA. Is this the exact behaviour of server side sync? With emails, the synchronization works in tow ways, is this an exception?

Best regards

Yan Ken