Hi,
Thank you for sharing your question. I understand how frustrating it can be when Bookings does not update calendar details in the app for customers using emails outside your organization.
This behavior occurs because Microsoft Bookings relies on organizational accounts for full integration with Microsoft 365 services. When a customer uses a personal or non-business email, the booking is confirmed and appears in Outlook, but the synchronization to the Bookings app may fail since the external email does not have permissions or identity linkage within your tenant.
To resolve this, ensure that your Bookings calendar is connected to the correct staff accounts and that external attendees are added as guests. You can also enable notifications and confirmations in Bookings settings so that all participants receive updates regardless of email type. Another option is to verify that your organization’s policy allows guest access and external sharing in Microsoft 365 admin settings, as restrictions can block updates from syncing properly.
I hope this helps.
Best Regards,
Noel