We have several staff who FW: emails to helpdesk. If they don't remove the FW: from the subject, the ticket is not created. Is there a way to create the ticket when there is a FW: or RE: in the subject line?
You could take a look in your mailbox and see what folder the email goes into. It's important to know if the email arrives or gets moved to the Helpdesk_ignore folder.
This might be related to settings you've set in Lansweeper. Take a look at your incoming mail settings in Configuration\E-mail settings. Maybe one of the filter rules is preventing the emails from being imported.