DS photo+ seems to actually require port 80 (regular HTTP) to stream videos even if it is being used in HTTPS mode. Therefore, to get DS photo+ to stream your videos from outside your LAN, you will need to configure your router or firewall for port forwarding of port 80 (HTTP) in addition to port 443 (HTTPS).
The above was tested with DS photo+ version 2.0.1 on DSM 4.0 build 2228.


