Problem with forwarding ports firmware 6.8rc1

Hello,
Im trying to configure the NAT rule to forward ports for my Video camera. Ive set it like this : Action: dst-nat, chain: dstnat, src Address: external ip, dst Address: internal ip, Protocol : 6(tcp) src port : 5445, Dst port :88, in interface: ppp-out1 (WAN). I cannot set Out Interface because of an error, but I think it is not needed. At the camera Ive set Web Address at port 88 and it is reachable by internal network. External ports Ive set as 5445 to 5446 in the camera. However from outside it is not reachable. What am I doing wrong here ? The firmware of the router is 6.8rc1. Internet works without any problems at the router, external ip I can ping from other network through internet. Help please, the best with the graphics interface, not the text one.
Thanks Greetings