Power went out a few days ago.  After a few minutes, I went into the GUI and executed a proper shutdown.  I then turned off the UPS.

 

After power came back on, I turned on the UPS, and unraid. 

 

Now unraid cannot see the UPS, I get the red box of death "Communications Lost" in the status window popups, and under the UPS Settings it shows no communications with the UPS.

 

During and after the power outage, nothing changed or moved, no cables were unplugged, etc.

 

I just re-seated the USB cables on both the UPS side and the unraid side -- no effect.

 

Any ideas?

 

Thanks.

Months later the server can suddenly see the UPS again.

It just took some time to recharge the batteries.