Shared Calendar Editing Issue in Microsoft 365 Basic

We are experiencing an issue with a shared calendar in Outlook Web and would appreciate your assistance.

Our organization is using Microsoft 365 Basic licenses (non-Business). We have shared a calendar with multiple users and assigned them "Can edit" permissions.

Initially, only the administrator could see the shared calendar, while other users could not. This issue was eventually resolved, and all users can now see the shared calendar and its events.

However, we are currently facing another problem:

• Users can view all events in the shared calendar.
• Users can create their own events.
• Users cannot edit events created by other users, even though they have been granted editing permissions.
• When opening an event created by another user, the event opens in view-only mode and there is no "Edit" button available.
• We have verified that the permissions are correctly set to "Can edit" for all users.

Could you please confirm whether this behavior is expected when using Microsoft 365 Basic licenses and Outlook Web, or if there is an issue with the calendar permissions configuration?

If additional configuration is required, we would appreciate detailed instructions on how to enable full editing access for all users of the shared calendar.