openvpn client access to another subnet behind ipsec site-to-site tunnel

[a2940uw]

Hi All  , I have a question for how to let openvpn able to access other remote network which is connected with ipsec tunnel, for example I have two site A & B (different subnet) was connected with IPSec without problem, a openvpn client success connect to site openvpn server and able to ping site A all address but fail to site B, the server client already pushed two route 192.168.11.0 & 192.168.12.0 though the openvpn tunnel address assign to user, and firewall is already allowed access on both side, site A and site B able to ping each other in site A and B.

site A : 192.168.11.0/24
site B : 192.168.12.0/24
openvpn client tunnel address : 10.0.123.0/24

Thank you