Servers reporting to No VM Manager data

I can see servers reporting to No VM Manager data in ILMT console. what changes we can do on VM Manager ti avoid this issues

VM Manager connections and data are key to IBM Sub-capacity reporting. Please see the following link and others to configure and troubleshoot.

https://www.ibm.com/docs/en/license-metric-tool?topic=scshw-troubleshooting-outdated-vm-manager-data-no-vm-manager-data-statuses