Hi Rimccart, The NAK messages disappeared today after changing the dhcp port from trunk to access. I had configured the port that connect the dhcp server to trunk with native vlan 1. I think the dhcp server was responding to numerous dhcp requests from different vlans while on trunk hence generating the NAK messages. Happy this has resolved the issue. Thank you very much for your input. ... View more

Hi Rimccart,   We are still experiencing the same issue.   We had two dhcp servers on active active mode initially enabled for the affected SSID. From packet capture on the ports dhcp servers, ACK messages were only being received from on server. We deactivated the active active mode on dhcp and relay to the only one dhcp server were getting ACK messages from.    Firmware update did not also help.   Thanks. ... View more

Thanks Blake. DHCP lease pool is large. I am using less than 50%. I did reduce the DHCP lease time to 8 hours. I am still getting logs with the same error. Private MAC is disabled as well. ... View more

Noted and thanks Cmr ... View more

May be it can help, actually access switch that connect to the APs are MS120 and all running 15.22. The coreswitch is MS210. ... View more

Yes, using dhcp relay. Switch model - ms210-24p Firmware Version: MS 15.22 Will really appreciate the fixes. ... View more

Hi Marce, Thanks for the insight. I actually have a small number of devices (less than 200). On the network, we have a guest ssid with dhcp functionality that runs on the core switches. I will give it a try but I doubt if that will be the cause of the issue. When I connect device using cable on the same Vlan as the dhcp server, the devices connect immediately. ... View more