ESXi firewall is applicable only for ESXi network traffic as said above. This looks like an issue with your network or firewall within the VoIP server.
Try pining gateway.
Use tracert to check till which hop the packet routes to, based on that you can find where the packets getting dropped.
VoIP is able to ping 113.x/24 because they are in same network but not 114.x which requires routing. So the issue is at routing level.