Unfortunately it's a pretty generic error. Without looking at the log files there is no real way of knowing what the cause is. I'd recommend contacting our support team and including the following logs:
- Program Files (x86)\Lansweeper\Service\Errorlog.txt, as present on your Lansweeper server.
- Program Files (x86)\Lansweeper\Website\App_Data\web_errorlog.txt, if it exists.