I’ve got this error yesterday. I wanted to restart my Cluster Node, then this Message did appear. I was waiting for like 30mins and watched the server with ping “IP-Adress” -t . Then after 34mins i was able to connect again the Node.
Well its confusing, when your Servers are in the Datacenter and you are thinking, if you should go and manually shutdown the servers.
Well i’d recommend you should wait for like 30mins, until you go and manually restart your servers 
and don’t panic like me.
Best Regards
PS: Sorry for my bad english
IT-Guy from Switzerland