The ProxySG or Advanced Secure Gateway (ASG) is failing to boot.
When connected to the serial console and booting up, you see the AMIBIOS screen go by then it gets stuck on the next screen with an output like Booting from SATA PS: ATP IG SlimSATA Part1.
The primary boot device is connected, but there is an issue with the data on the disk.
Boot from the Secondary SSD (SS) by:
When the appliance boots from SS, there is a mirroring process done to PS. Thus, the data will be corrected on PS and a reboot will successfully boot from it now.