I just got my C5400X today and tried to set the port forwarding to work but unfortunately I tried everything I can find online, no vail. I tried to roll back to older firmware, still not working. Revert back to latest firmware, still not working either. Please advise, thank you!

Just to add more details, the port forwarding I was trying to set was for transmission, mainly for torrenting purposes. I switched from a Netgear R7000, which had the port forwarding properly previously before I switched.