prism Node dsicovery failed

Ate they turned on and booted into ahv? On the same vlan as the current production nodes? 

So this node are new HPE with AOS LTS branded,  HV not yet installed  , so the networker said the maschine is connectetd to the  same vlan as the production cvm, ilo(ipmi) is rechable per  default ip

when you say AOS is already installed , that means the hypervisor (AHV/ESXI/Hyper-v) is already installed as well.

if they are already connected to production switch,I will check the tag (vlan ) of both AOS and hyper-v to make sure they are on the correct vlan.

are you able to reach both aos and AHV IPs from your Prism? if the ping is reachable, you should be able to see it in prism

Nutanix certified hardware come pre-installed from the factory. You only need to add the ip information and vlan information to create (or expand) the cluster. You can do this with the crashcart. More info about that is here: https://www.jeroentielen.nl/the-nutanix-network-crashcart-a-hidden-gem/

When the nodes have there ip information you can expand your cluster. 

OR: (So this is another method) you can run foundation to install the same version as the production versions (aos, ahv) and set the ip config during foundation.