I've got several APC AP8853 rack PDUs. All of which are assigned IP addresses and connected to the network. However, after some time I noticed I cannot access some PDUs by their IP address even though they used to work fine. In order to overcome this I have to connect to the PDU through the serial port and restart the monitoring module from there or do a hard reset using pin head. This is so inconvenient. I have googled to see if there is any help and found this link
However, the firmware version on those units is 6.5.6 as per attached screenshots.
I'm looking for your support. Thanks.
First thing I say is upgrade the NMCs to 6.9.6:
Choose a location