Clients not receiving an IP after certain amount of users is connected to wifi

[JakoRockA]

Hi All
Hope someone can help me figure this out or point me in the right direction.

Hardware:
Controller: ZoneDirector  ZD3025
APs: r500 and r610
DHCP server: Windows DHCP
We have 4 SSIDs Officenet1 and 2, CustomerNet1 and 2.

The Issue:
When about 160 end devices collectively are connected to the Ruckus controller on various SSIDs, an issue happens where clients are having trouble receiving an IP from the DHCP server. So Often the Client is connected to the controller, but is displayed without an IP. It might even reset the wifi network card on the client to then try to reestablish the connection. Or the connection on a windows laptop will state "No internet, Secured".
If I give my laptop a static IP it will work without any issue.
But the SSID with the fewest clients connected to it, will have a higher chance of getting an IP.
And there are plenty of available IPs to lease from all the 4 networks.

Does anyone have any idea of what I can do?

[Squozen]

Have you checked the DHCP server logs to see if it’s getting the DHCP requests?

[JakoRockA]

I tested again, and it seems like it's not reaching the DHCP server, at least not on the most "crowded" networks.
but after 5 minutes one of my phones reached the DHCP server, and all I can see in this log:
C:\Windows\System32\dhcp\DhcpSrvLog-Tue.log
is this:

10

05/28/24

08:03:56

Assign

1921681162

Galaxy-S22-JMJ.CUBIC.GUEST

MAC-address

For some reason traffic does not reach the DHCP server, and the error typically appears after a certain amount of Clients is connected to the ZoneDirector (is my guess).
At least when fewer clients is connected I do not have the issue.

I also checked event viewer but I cannot find any logs related to my two phones I tried with.

When I go to the ZoneDirector -> Trobleshooting -> Client connectivity -> I see that one of my phones send out a DHCP discover message but received no answer. 
But again, for the first 160 clients or so, it works completely fine. It's strange.