Can't manage to use port forwarding.

both apps (synology and paradox) where working fine with my old router.

Î ve checked everything I could find ln the forum:

external ip is public

upnp is disabled,

Target internal ips are in dhcp and reserved

when connected on internal wifi, both'applications work fine (using port 5000 and 10000)

when external, no connection. 
just like if the port fowarding was not enabled.

what can I do??

thanks