Proxmox : Web GUI not updating the Datacenter status

Problem with proxmox GUI and cluster management.
From one node of the cluster I saw on /var/log/syslog file that

 Apr 12 16:34:37 t1 pveproxy[2502]: proxy detected vanished client connection  

and when we¬†access to the Web GUI of that node, Show Node ‘t1’ is down.
The solution is to simulate a reboot of all the machines without rebooting the VM on them.
So this is the sequence to launch on every node of the cluster, without some particular order

 /etc/init.d/cman restart  
 /etc/init.d/pvedaemon restart  
 /etc/init.d/pvestatd restart  
 /etc/init.d/pve-manager restart  
 /etc/init.d/pve-cluster restart  

Now, it works great.