Calendar reminders are not applied

Hi everybody,
At first tnx for your job.
I’am a new user of nextcloud and i just made a fresh install of the release 12.0.3 of NC.
I may be missing something, but I can not run reminders of calendar.
No window, no email, no sound, even if the reminders are configured for an event.
No error in the log.
The test email works find and it sent when there is a new calendar event.

Thank you for your help and best regards.