You have deployed an SRX300 Series device and determined that files have stopped being scanned.

SRX300 Series devices support an on-device antivirus scanning engine, Avira, that scans the data by accessing the virus pattern database. It provides a full file-based antivirus scanning function that is available through a separately licensed subscription service. However, there is a limit on the number of files that can be submitted for scanning per day, depending on the SRX platform size. If you exceed this limit, the files will not be scanned until the next day. The limit for SRX300 Series devices is 1000 files per day1. References: SRX Series On-Device Antivirus Scan Engine Overview