WMI Scan on non-domained Windows devices

We have numerous Windows workstations on our LAN that are not a part of our Windows Domain. Each of these PCs has a standardized local administrator account. I would like to use WMI scanning on these devices. Can someone advise regarding the correct entry into the Credential Manager to allow the local admin credentials to be used.

For purposes of example, let's say the local Admin account on these devices is always "LocalADM". I have tried entering LocalADM in the User Name field along with the corresponding password. It fails. I have also tried entering .\LocalADM as the User Name. It also fails.

Any suggestions?