The BMC become unreachable in-band and out-of-band whatever the tool (ipmitool, SMCIPMITOOL, SUM, AlUpdate etc..).
The only way to power on the nodes again is the blade button BUT the blade stay in state "initializing states / AF" for a very, very, very long time and sometime during hours
Checked the firmware of your system and found the one you have is in "older" version. PLease update to current available Version listed on our product website
FYI,
If your system use is using OEM-FW, the “public” FW update may cause other issue in your system.
Please request most up to date BMC/BIOS FWs from your sales contact for continue process.