Exchange 2013's Antispam

Hi All

I have Exchange Server 2013 which has Mailbox role and Client Access role installed.

I have enabled Antispam but users still received lots of spam mails.

I checked the Quarantine mailbox and noticed that only Content Filter agent able to quarantine the mails. Other agents seems like not working well.

Is there any way to improve the Exchange's Antispam?

Thanks.