All of my computers keep going to Non-Active status when Lansweeper fails to scan them. For example I have a computer that was scanned on Friday the 13th but failed to scan on the 19th and Lansweeper set it to Non-Active. I verified my server settings and verified that it is not support to set to Non-Active till after it has not been seen for 30 days.
If I force a re-scan when the computer is up and running it goes back to active.