hi...
i just recently changed my two m21s farm and as the first day i receive these errors :

 210    Power error status: 0x0001->0x0000
 250    Power input undervoltage protection 0. code: 0x00020000

and the events in my miner page is :

 E006  Slot1:zero_HS    Restart cgminer     4    Fri Nov 15 03:45:09 2019   cgminer

why all of my m21s devices are giving these errors ?
 
I have m20s and a s17 there too

but they are working well