Standalone installation of LiveAgent software doesn't have any spam filter by itself. Marking a ticket as spam is the job of the mail server by which the email is received. Additionally, it is possible to install SpamAssassin on your server. You can also use the SpamAssassin plugin directly in your LiveAgent which you can set up in Configuration > System > Plugins and configure it to use some external server where the actual SpamAssassin service is configured so before a ticket is created from an email in LiveAgent the email will go through that external SpamAssassin service and if the email is recognized as spam a ticket marked as Spam will be created in LiveAgent.
SpamAssassin Setup
Step 1: To activate SpamAssassin plugin navigate to Configuration>Plugins>SpamAssassin integration
Before you activate this plugin, please make sure, that SpamAssassin is installed on your server. Emails marked as spam can be still found in the tickets marked as spam.
Step 2: Firstly Buy this feature for $99
then click on Activate button and LiveAgent will automatically restart
Step 3: Click on Configure button and enter IP or hostname of your SpamAssassin server and port number of SpamAssassin service
Additionally you can check “Teach” You can teach SpamAssassin, when mail was manually marked as spam to improve quality of spam recognition. Warning: Must be enabled on SpamAssassin server.
Step 4: Navigate to Configuration>Email>Mail accounts choose your email address already connected to LiveAgent and click on Edit
Step 5: Check "Process with SpamAssassin"