I have seen many times that User do not get IP address from the DHCP server and when I restart the interface where ip helper address is present and flush the ARP table it generally statrt working.
I am confused what cause the issue as when I check the DHCP server it is always reachable and there is no issue on DHCP server and user who were conncted they are working fine bt new user do not get the IP address and pool is also available.
Is there is a issue on Cisco switch for DHCP relay or something else.
Any help will be appreciated.
Can you post the config of the cisco switch?
Do you have secondary ip addressing on the L3 interfaces?
Does all the dhcp pools have enough ip address available?Do you more than one dhcp server active?