VDP 5.5 failed to retrieve the storage information on the appliance

hi guys

All of a sudden VDP stopped working, when I try to access VDP from Web Client I get a popup saying:

"The VDP Appliance is not responding. Please try your request again.Would you like to be directed to the VDP Configuration utility to troubleshoot the issue?"

and once there in the Configuration Utility, all services are OK, I only see this with a red X

Failed to retrieve the storage information on the appliance

Any idea what's going on?

thanks a lot