thank you for this answer, but we've already checked the status
both controller and switch link status are up
I tried many times by disconnecting and connecting cables
but unfortunately the same thing
is it possible to resolve the problem if we try a ping for 5 or 10 hours ??
If you are sure that the IP settings are correct on both controllers, and the ping does not work for a direct connection (without hub or switch) between one controller and a server, then you will need to reboot the controller which is not responding to the ping.