I don't mind starting again and will probably do that. I think the answer is ignore the GUI and do it by CLI as the GUI does it incorrectly? If it's the latter I thought you guys should know. I don't know, It seems strange to me that the nodes are using two seperate networks 172. for proxmox. 192 (which is what proxplay,cluster.rml resolves to). You can see in post 15 I'd manually changed corosync to use the same network Something, not me, (in post 19) seems to have changed it back to be the wrong networks. I've no idea how that happened but potentially on reboot? Question: Should corosync be showing the same network, and what could have changed this? Should pve/.members be the corosync network or the normal one? Was it though? Or have you a problem the GUI setup? Either way, thanks to both of you for your help. It's massively appreciated. Have a top weekend.