no-ip problem

i have mt 5.20 x86 i search anywhere i cannot find any idea about my problem so i post here
i have 2 mt one for load balacing and other for user, load balancing mt is behind the user mt i apply script on user side mt ,it is working fine inside network but i cannot access it outside of network. when i ping dns from my mobile or outside network it gives request time out.
there is not filter rule just simple masquerade NAT.