Cannot Remote control XP machines that are part of a workgroup.
Agent is configured to use Windows NT security/ local template.
LDMS administrator is member of Remote Control operator.
Administrator does a right click on a machine from within All Devices folder.
Remote session start and the LDMS Administrator is prompted for his credentials. Although the credentials are correct nothing happens, LDMS is still prompted for credentials.
On XP machine , run secpol.msc
In Local Security Settings look for parameter "Network access:sharing and security model for local accounts"
Configure the parameter to be " classic-local users authenticate as themselves"
Reboot the machine.
You could also do it via registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\ForceGuest set to 0