Foreman fails to create reservation (isc-dhcp-server) when creating a Host

Problem:
I have a really straightforward isc dhcp server (installed through packages on Ubuntu 22.04).
When I try to create a host on Foreman, I get the following error message:

Create DHCP Settings for demo.mydomain.com task failed with the following error: ERF12-6899 [ProxyAPI::ProxyException]: Unable to set DHCP entry ([RestClient::Exceptions::ReadTimeout]: Timed out reading data from server) for proxy http://foreman-smart-proxy.mydomain.com:8000/dhcp

Expected outcome:
The creation process should be successful and the reservation should be created on the DHCP server.

Foreman and Proxy versions:
Foreman: 3.12.0
Foreman proxy: 3.12.0

Foreman and Proxy plugin versions:
foreman_discovery: 24.0.2
foreman_puppet: 7.0.0

Distribution and version:
Ubuntu 22.04
isc-dhcp-server: isc-dhcp-server/jammy-updates,now 4.4.1-2.3ubuntu2.4

Other relevant data:

DHCP server configuration

omapi-port 7911;
key "omapi_key" {
        algorithm hmac-md5;
        secret "xxxxx";
};
omapi-key omapi_key;

option domain-name "mydomain.com";
option domain-name-servers 192.168.86.2;
option routers 192.168.86.1;
option subnet-mask 255.255.255.0;

default-lease-time 600;
max-lease-time 7200;

ddns-update-style none;

authoritative;

subnet 192.168.86.0 netmask 255.255.255.0 {
  range 192.168.86.5 192.168.86.251;
  option routers 192.168.86.1;
  option broadcast-address 192.168.86.255;
}

host bastion  {
  hardware ethernet xx:xx:xx:xx:xx:xx;
  fixed-address 192.168.86.36;
  option subnet-mask 255.255.255.0;
}

foreman-smart-proxy logs

2024-10-30T09:51:33  [I] Successfully initialized 'foreman_proxy'
2024-10-30T09:51:33  [I] Successfully initialized 'dns_nsupdate'
2024-10-30T09:51:33  [I] Successfully initialized 'dns'
2024-10-30T09:51:33  [I] Successfully initialized 'tftp'
2024-10-30T09:51:33  [I] Starting allocated ip address maintenance (used by unused_ip call).
2024-10-30T09:51:33  [I] Successfully initialized 'dhcp_isc'
2024-10-30T09:51:33  [I] Successfully initialized 'dhcp'
2024-10-30T09:51:33  [I] Successfully initialized 'logs'
2024-10-30T09:51:33  [W] Missing SSL setup, https is disabled.
2024-10-30T09:51:33  [I] Smart proxy has launched on 1 socket(s), waiting for requests
2024-10-30T09:54:02 d93042e7 [I] Started GET /dhcp/192.168.86.0/unused_ip mac=bc:24:11:d0:61:6e&from=192.168.86.100&to=192.168.86.200
2024-10-30T09:54:04 d93042e7 [I] Finished GET /dhcp/192.168.86.0/unused_ip with 200 (2012.33 ms)
2024-10-30T09:54:21 42ec76c2 [I] Started GET /dhcp/192.168.86.0/mac/bc:24:11:d0:61:6e
2024-10-30T09:54:21 42ec76c2 [I] Finished GET /dhcp/192.168.86.0/mac/bc:24:11:d0:61:6e with 200 (4.06 ms)
2024-10-30T09:54:21 42ec76c2 [I] Started GET /dhcp/192.168.86.0/ip/192.168.86.101
2024-10-30T09:54:21 42ec76c2 [E] No DHCP records for IP 192.168.86.0/192.168.86.101 found
2024-10-30T09:54:21 42ec76c2 [W] Error details for No DHCP records for IP 192.168.86.0/192.168.86.101 found: <Exception>: No DHCP records for IP 192.168.86.0/192.168.86.101 found
2024-10-30T09:54:21 42ec76c2 [W] No DHCP records for IP 192.168.86.0/192.168.86.101 found: <Exception>: No DHCP records for IP 192.168.86.0/192.168.86.101 found
2024-10-30T09:54:21 42ec76c2 [I] Finished GET /dhcp/192.168.86.0/ip/192.168.86.101 with 404 (3.99 ms)
2024-10-30T09:54:21 42ec76c2 [I] Started POST /dhcp/192.168.86.0
2024-10-30T10:23:19 527d009e [I] Started GET /version
2024-10-30T10:23:19 527d009e [I] Finished GET /version with 200 (0.66 ms)

It seems that the proxy is able to get a free IP address but is unable to write the reservation.