Network problem in mikrotik Hotspot

Hi every body, recently I set up Mikrotik RB951 Hotspot. everything works fine but our users in our Network report that our
organizational program lost its connection to server randomly and program terminates with connection failure .
all client and servers are behind the hotspot in same network address range , but i do not know why this happens.

hi
in
ip–>hotspot–>server–>address pool=“none”
and
ip–>hotspot–>user profiles–>address pool=“none”

ip–>hotspot–>server–>address pool=“none”
When you do this client was allowed to mac-spoofing, client can get a lot of IP’s with the same mac-address !

thank you soooo much friends .. it worked and problem solved.