DHCP is not sending DHCP ACK

Hello! I have vpn server and MikroTik that offer dhcp leases to clients, i.e schema like

Client → VPN server → MikroTik

With first client that want to offer ip address DHCP works fine:

12:02:01 dhcp,debug,packet vpn-dhcp received discover with id 1246955413 from 10.0
.10.2
12:02:01 dhcp,debug,packet     flags = broadcast
12:02:01 dhcp,debug,packet     ciaddr = 0.0.0.0
12:02:01 dhcp,debug,packet     chaddr = 7A:A7:6D:51:4E:FC
12:02:01 dhcp,debug,packet     Msg-Type = discover
12:02:01 dhcp,debug,packet     Client-Id = 62-6F-72-74-6E-69-6B-6F-76-40-65-74-65-
63-61-72-2E-72-75
12:02:01 dhcp,debug,packet     Parameter-List = Domain-Server,NETBIOS-Name-Server
12:02:01 dhcp,info vpn-dhcp deassigned 10.0.10.6 from 7A:A7:6D:51:4E:FC
12:02:01 dhcp,debug,packet vpn-dhcp sending offer with id 1246955413 to 255.255.25
5.255
12:02:01 dhcp,debug,packet     flags = broadcast
12:02:01 dhcp,debug,packet     ciaddr = 0.0.0.0
12:02:01 dhcp,debug,packet     yiaddr = 10.0.10.6
12:02:01 dhcp,debug,packet     siaddr = 10.0.10.1
12:02:01 dhcp,debug,packet     chaddr = 7A:A7:6D:51:4E:FC
12:02:01 dhcp,debug,packet     Msg-Type = offer
12:02:01 dhcp,debug,packet     Server-Id = 10.0.10.1
12:02:01 dhcp,debug,packet     Address-Time = 86400
12:02:01 dhcp,debug,packet     Domain-Server = 10.0.10.1
12:02:07 dhcp,debug,packet vpn-dhcp received request with id 1246955413 from 10.0.
10.2
12:02:07 dhcp,debug,packet     flags = broadcast
12:02:07 dhcp,debug,packet     ciaddr = 0.0.0.0
12:02:07 dhcp,debug,packet     chaddr = 7A:A7:6D:51:4E:FC
12:02:07 dhcp,debug,packet     Msg-Type = request
12:02:07 dhcp,debug,packet     Client-Id = 62-6F-72-74-6E-69-6B-6F-76-40-65-74-65-
63-61-72-2E-72-75
12:02:07 dhcp,debug,packet     Address-Request = 10.0.10.6
12:02:07 dhcp,debug,packet     Server-Id = 10.0.10.1
12:02:07 dhcp,debug,packet     Parameter-List = Domain-Server,NETBIOS-Name-Server
12:02:07 dhcp,info vpn-dhcp assigned 10.0.10.6 to 7A:A7:6D:51:4E:FC
12:02:07 dhcp,debug,packet vpn-dhcp sending ack with id 1246955413 to 255.255.255.
255
12:02:07 dhcp,debug,packet     flags = broadcast
12:02:07 dhcp,debug,packet     ciaddr = 0.0.0.0
12:02:07 dhcp,debug,packet     yiaddr = 10.0.10.6
12:02:07 dhcp,debug,packet     siaddr = 10.0.10.1
12:02:07 dhcp,debug,packet     chaddr = 7A:A7:6D:51:4E:FC
12:02:07 dhcp,debug,packet     Msg-Type = ack
12:02:07 dhcp,debug,packet     Server-Id = 10.0.10.1
12:02:07 dhcp,debug,packet     Address-Time = 86400
12:02:07 dhcp,debug,packet     Domain-Server = 10.0.10.1

But with second client in log I see some errors, it’s looks like DHCP offer lease, but does not send DHCP ACK, so client could not finish establish connection:

12:04:14 dhcp,debug,packet vpn-dhcp received discover with id 3591468449 from 10.0.10.2
12:04:14 dhcp,debug,packet     flags = broadcast
12:04:14 dhcp,debug,packet     ciaddr = 0.0.0.0
12:04:14 dhcp,debug,packet     chaddr = 7A:A7:E4:62:05:09
12:04:14 dhcp,debug,packet     Msg-Type = discover
12:04:14 dhcp,debug,packet     Client-Id = 67-75-73-68-63-68-69-6E-40-65-74-65-63-61-72-2E-72-75
12:04:14 dhcp,debug,packet     Parameter-List = Domain-Server,NETBIOS-Name-Server
12:04:15 dhcp,debug,packet vpn-dhcp sending offer with id 3591468449 to 255.255.255.255
12:04:15 dhcp,debug,packet     flags = broadcast
12:04:15 dhcp,debug,packet     ciaddr = 0.0.0.0
12:04:15 dhcp,debug,packet     yiaddr = 10.0.10.8
12:04:15 dhcp,debug,packet     siaddr = 10.0.10.1
12:04:15 dhcp,debug,packet     chaddr = 7A:A7:E4:62:05:09
12:04:15 dhcp,debug,packet     Msg-Type = offer
12:04:15 dhcp,debug,packet     Server-Id = 10.0.10.1
12:04:15 dhcp,debug,packet     Address-Time = 86400
12:04:15 dhcp,debug,packet     Domain-Server = 10.0.10.1

Does anybody could help me with this kind of error?