I found the problem. In my dhcp server ( in server manager) in the fqdn or ip field: I had set 192.168.1.1,192.168.1.2 (primary and secondary) the system considers because of the comma that it is a fqdn and not two ip addresses . So either you have to put a single address in the fqdn or ip field or put both addresses in the Ipv4 field.