Hi @Cory Leach ,
According to my search, some users have been experiencing the same problem with private links not working in Bookings. The issue seems to be related to a recent update, and Microsoft is working on a fix. In the meantime, some users have found a workaround by sharing public links instead of private ones. See: https://techcommunity.microsoft.com/t5/microsoft-bookings/this-link-is-not-valid-for-bookings/m-p/3911425
Please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client and your issue is more related to Microsoft Booking. To better help solve your issue, it is recommended that you post a new thread to the dedicated forum for Microsoft Bookings .
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