Appointments made to exchange accounts on MacOS is not syncronised to clients running on Windows

I’m running eM Client on macOS with several Exchange mail accounts. I have the problem that if I make an appointment in an Exchange account with Em Client for macOS, the appointment is not reflected on the Exchange calendar server and consequently not reflected in any mail clients running, e.g., on Windows/web and not any other client on macOS (e.g., Calendar). This makes it impossible to use eM Client for macOS for new appointments, etc., as appointments disappear. If I make an appointment on eM client for Windows

Running eM Client 10.4.4924, macOS Tahoe 26.4 those errors do NOT show here.
eM Client with 2 Exchange accounts, calendar events are shared via Exchange server and NOT via icloud and there are shared with iPhone, iPad and other Mac almost instantly.
Did you check your settings? Settings → Internet accounts and then look at your accounts and see what you share.

I think it’s a bit more complicated than that. It seems to be a common problem, and the EwS team is working on a solution. The only workaround presently is to make appointments in macOS Calendar.