We normally advise it to be installed on a VM. That means that VM can also be protected with B&R and then be stored on a USB device (as a whole VM) or the cloud backup. Advantage of doing this is that you can recover from within the B&R console also. For example, when you have the VM as a backup, and for some reason the O365 server is damaged or whatever, then you can still restore from the B&R repository, and we will even recognize that it is a O365 server and immediately give you the option to use VEX on that one.
But again, as said. It is a supported scenario to have them both on one server, and if you have that issue above, I would ask you to work with support to figure out what is wrong
Hope my explanation makes sense