Thank you, we received your mail. The mapping of credentials seems to be ok. The "Access denied" message can sometimes be caused as well through firewall issues. In order to perform WMI scans, port 135/TCP and the dynamic port range (49152-65535 on Windows Vista and more recent OS versions) need to be open between your scanning server and scanned computers. Possibly this range is blocked and therefore Lansweeper can't connect.
If you can't open that range, you could either configure a fixed WMI port on all affected target computers or scan them with LsPush. This is a small executable which scans the computer and sends the result back to your Lansweeper server using direct server connection (port 9524/TCP by default), file share or mail. You can find details
here. It is possible to configure a scheduled task for running LsPush and deploy it via group policy.
Other possible causes of an "Access denied" message are explained in
this KB article.