I’m not an expert of Exchange, but I wasn’t able to find something clear in the documentation saying I must install new Exchange server (2016) on the same site as existing one (2013) and move it later!
Anyway, the list of errors I got in the Readiness Checks page wasn’t useful at all. However, looking at the ExchangeSetup log file was.
If you are receiving something like:
Global updates need to be made to Active Directory, and this user account isn’t a member of the ‘Enterprise Admins’ group
You must be a member of the ‘Organization Management’ role group or a member of the ‘Enterprise Admins’ group to continue
And you’re sure the account running the setup has these rights, then most likely you’re trying to install the first Exchange server of this version on AD site that has no Exchange servers at all.
My solution, actually it was a work around, was simply to move domain controllers to a site with Exchange servers, remove the subnet from AD Sites and Services, and reboot the new Exchange server.
After 15 minutes, just enough time for AD replication to take place, I logged in again to the server and started the Exchange setup, and it works just fine.