Microsoft Bookings double-booking staff despite busy calendar entrie

Hello everyone,

We are experiencing an issue with Microsoft Bookings. Our setup allows external customers to book appointments via the published booking link on our website. However, we have noticed that staff members can still be double-booked, even when their Outlook calendars show them as “Busy.”

Here’s what we have already done to try to resolve the issue:

1. Ensured that the option “Events on Office calendar affect availability” is enabled for all staff in Bookings.
2. Verified that in Outlook, the staff calendars have appointments marked as “Busy” to reflect their availability.
3. Shared staff calendars with the Bookings account and set default permissions to “When I’m busy”.
4. Checked that the booking page settings are set to respect staff availability.

Despite these steps, the system still allows bookings to be made during times when staff are busy.

Our staff mailboxes are hybrid (both on-premises and in Exchange Online), and we are running a hybrid setup in general.

We are wondering if anyone else has experienced this issue and if there are recommended solutions or workarounds.

Thank you for any insights!