DHCP and IP advertising router

DHCP does not work on one of our subnets (vlan87)
also, when using our Fluke tester to auto-discover the network on the above subnet/vlan87, it says “no ip advertising router found” – What does this mean? what advertising? what packets? what parameters on the router is it referring to?

we think this might have something to do with our dhcp problem.
Can you also talk about DHCP? what type of packets, broadcasts? or whatever details about it that might give us a clue to what’s causing dhcp not to work