WOl requests are now sent by the lansweeper service (in the past this was sent from the computer browsing the website) Make sure the server is in the same subnet and that no firewall is blocking the requests.
I run it from the "Summary" page of a computer by clicking "Wake On LAN" under the Asset Options. No error messages. It has worked in Lansweeper for us in the past. I have a computer next to my desk that worked before and now it won't We haven't made any changes to the BIOS that would disable it.
Please clarify how you are running the tool and what happens when you run it. If there is an error message, send a screenshot to support@lansweeper.com