We are doing an annual test on our core switches on each site. Our site on YOK we have a Cisco 9500-40X when I did a fail over test with Local IT I have him unplug the power cable on Core 1 and Core2 should automatically take over right? however what weird is when the power cable on Core1 was unplug we don't have internet on office LAN/WAN I can't even ping the MGMT IP's of our Firewalls and Core switch. What weird is after we started to plug back power cable of CORE1 after 10 minutes Core2 is taking over and we can access everything. When I unplug the Core2 Power cable the Core takes over immediately in less than 5 secs. Which opposite of Core 2. Did you encounter this kind of issue? So my work around as of now Core 2 is set as primary and the Core 1 is set as standby.