Hypex NC400 Amp Problem

Greetings,
I'm new here but have been using a pair of NC400/SMPS600-V3 mono-amps for a few years. I'd appreciate any comment or help to troubleshoot an issue with one of the amps.
The amps have been plugged in but powered off for about a year. Upon turning on a few days ago, one amp did not respond. The fuse is not open. The caps, coils, and visible components appear to be intact and good shape. However, the row of LEDs in the middle of the NC400 module flashes red at every 2 seconds.
How do I find the error? Will I need to replace either the Amp or the PS module? I've written to Hypex but haven't receive any reply yet.



Thanks in advance for your time and help.