Why some of the services still not work even EZ Router/Port forward enabled?
Some of the router will use specific service ports by default(for example webserver/80,443 FTP/21 ssh/22).
In this case, even the compatible router's UPnP was enabled and ADM-Settings-Manual Connect-EZ Router was activated, the services/app(such as FTP, terminal, Photo Gallery and phpMyAdmin) still not able to be used from outside of the network.
The issue could be solved by changing the service port in ADM-Service like WebServer from 80 to 8080 and 443 to 4430, FTP from 21 to 2100, then you should be able to access these services from out side of the network.
*Currently we find ASUS compatible router model do have this issue, please try mentioned method to change NAS's service port to clarify if its caused by router.