AV1200s, AV1400s, and AV2400s unable to ping devices after upgrading to 126.96.36.199 or newer releases.
AV1200s, AV1400s, and AV2400s are unable to ping IP addresses from the management console ping utility or using the serial console's ping command if the ProxyAV is running 188.8.131.52 or newer.
This is a bug 166339.
The only workaround to this issue is to downgrade the ProxyAV to 184.108.40.206 and then run restore-defaults from the serial console. Doing this restores the configuration to default and the ProxyAV will need to be reconfigured.