Why is the computer not getting an ip address via dhcp?

Question

Computer networks

There is a network. DHCP server, router - on Kerio. There are unifi ac-pro points with a cloud key controller. These points only distribute wifi. They are neither routers nor dhcp. Faced the following problem.
When connecting a laptop via wifi, it does not receive an ip address. API works.
Restarting the laptop does not help (just like reconnecting).
Only restarting the point helps. At the unify forum, they believe that the problem is in kerio. But this version is opposed by the fact that the problem occurs only at Wi-Fi points and does not occur on wires. And besides as reboot of a point helps, instead of reboot of kerio. And in general, apart from overflowing the dhcp pool, I do not know the reasons why it cannot issue an ip address. If you register the address manually, then everything functions.
Give me a hint where to dig and how?

Answer 1

And in general, apart from overflowing the dhcp pool, I do not know the reasons why it cannot issue an ip address.

Well, why immediately overflow the pool ...
And you do not consider the banal unavailability of the DHCP server? Problems with UDP traffic, problems with broadcast traffic in a wireless network?