After you replace the indicated hardware memory module the PRTG ESXi Hardware Status sensor error still does not clear.

If you check in Vcenter under the esxi host -> Monitor -> Hardware Health -> Storage Sensors it lists the message “Memory The physical element is failing”.

To fix go to System Event Log tab and select “RESET EVENT LOG”.

Then refresh the PRTG sensor and it should now return the correct status.

More info on VMware KB article: Warnings in the Hardware Status tab of an ESXi host fail to clear (2061093) - https://kb.vmware.com/s/article/2061093