scanning a workstation through SDP console keep saying "FAILURE :Failed to communicate the agent"

scanning a workstation through SDP console keep saying "FAILURE :Failed to communicate the agent"

Hi there,

SDP version: 8.2.0 Build 8217
Workstation has agent installed and updating the asset changes successfully.

Issue:
When I logged in to the SDP console and view the workstation, I click the [Scan Now] button but it keeps coming up with the error "FAILURE :Failed to communicate the agent".
On the workstation, if I restarted the service "ManageEngine AssetExplorer Agent", it successfully update the changes to the server.
I've tried to change the scan credential to use Windows Agent and domain credential, none works.

Firewall is off on both the server and the workstation.

Really appreciate any advice.

                  New to ADSelfService Plus?