The security appliance in the network XXXXXXX was unable to issue an IP address to new clients on subnet 192.168.1.0/24'192.168.1.1 because it has exhausted its pool of DHCP leases. New clients will not be able to connect to the network until this issue is resolved (e.g. by increasing the size of the subnet).
I have seen this before on a MX using its dhcp mechanism. There was a rouge ip phone that kept changing the last part of its MAC address and it kept consuming IP’s until the pool was exhausted. The dashboard however showed plenty of available addresses. After a call to Meraki support they were able to dig deeper and they could see that the pool was indeed exhausted. It is my understanding that the dashboard only shows successfully accepted dhcp offers. The rogue IP phone in question just kept flipping the last part of its mac and exhausted the pool. Sadly whenever the event occurred I wasn’t available to perform a capture.