On-Prem Exchange

[doubleaa]

I am trying to use Microsoft Bookings within O365 but my exchange sever is on prem and not in O365. I am getting an error message when starting up the bookings app. Can On-prem exchange be used or does this app only require O365 exchange in cloud. 

[#2]

Only users having their mailbox in the cloud can access it.

https://techcommunity.microsoft.com/t5/Microsoft-Bookings/Setting-up-MS-Bookings/td-p/110864