move vcenter to a new hardware (windows, new name, new ip, new sql server instance)

Hello together

We tried to move our vcenter to a new hardware as mentioned in VMware KB: Migrating vCenter Server to a different host machine

Unfortunately this does not work. When I try to connect with vsphere client, we get the error:

"vsphere client could not connect to <ip>. An unknown connection error occured. (The server could not interpret the client's request. (The remote server returned an error: (404) Not found.))"

I installed all the modules, with the simple installation method.

Is it possible, that the IIS is the problem on the new server? This one is already installed the and in use. I changed the ports of vcenter, but could this be the problem, because we are migrating also the db-data?

Thanks for your ideas.

Christof