Full Day Booking

same here ! After placing a support ticket and adding the URL of this page, the engineers found the problem below and everything was fixed this morning

We got an update from engineering.  Engineering identified the code changes that resulted in the issue and are working to disable them which could take anywhere from 6 to 8 hours. 

More info: When attempting to book sessions in the Microsoft Bookings 'Booking page', users are told to reload the page and are unable to book a session.

Current status: Our analysis of HAR trace files revealed that a recent update intended to optimize an unrelated feature introduced a code regression which interfered with users' ability to book full-day appointments through the 'Booking page' in Microsoft Bookings. To resolve this issue, we're disabling this feature update and anticipate that this change will take effect to resolve impact for all users by our next scheduled update. Scope of impact: Your organization is affected by this event, and any user attempting to book full-day appointment sessions in the Microsoft Bookings 'Booking page' may experience impact.

Here is the number of the Microsoft Incident if you need any help : MB458621