I have installed ubuntu-16.04.1-server-amd64 on a HPE ProLiant XL270d Gen9. The installation is fine, it is booting correctly.
Since I'm not located nearby the data center, therefore, I installed the operating system via iLO remote console (iLO->Remote Console -> Java web start) using the latest Chrome version on MacOS. After booting and login into the operating system, the remote console shuts down automatically.
I also activated the iLO Advanced License (Free Trial).
Since SSH-Server is not yet installed on Ubuntu I have no possibility to login into Ubuntu. I think that is a standard problem. However, I do not know how to resolve it.
Resolved see below.