The best would be to have a look into the errorlog Program Files (x86)\Lansweeper\Service\errorlog.txt on the new scanning server. If there is a database connection issue or a database user logon issue you need to fix that and restart Lansweeper service on that machine. Instructions on how to reset the database user and update the service config file can be found in
this KB article.
General instruction on how to install multiple scanning servers can be found
here.
If you could not solve it, could you send us the errorlog from the new scanning server together with a link to this forum topic in a mail to support@lansweeper.com.