For me, I had to do a number of things to get this to work:
- My ATT gigabit fiber modem was blocking the port, so I had to forward WAN requests on TCP port 5199 to my internal network router
- on my internal network router I set a static IP address for my JRiver machine, and then forward port 5199 to that
- on my JRiver machine, open JRiver, go to options, media network, click access key, and select to test it. This gave me the option to set the Windows Firewall exclusions
- then on my JRiver machine, configure the antivirus' built in firewall to allow the traffic
Then I could get to the media server from the WAN.
So the blocks that needed to be passed through in my case were cable modem --> router --> windows firewall --> bitdefender firewall
Since I'd only be accessing this from the outside using my cellular connection, I then went back into my router and added a rule to the port forwarding (step 2 above) to only allow forwarded traffic from specific IP ranges. (in my case, running Untangle, but you can also do this with Source Net rules in dd-wrt and others) For this, I included the IP range for my local network "192.168.10.0/24", the IP range for JRiver's servers "216.14.187.160/27", as well as my cellular provider's network ranges. (In my case this is ATT, so I googled what the cellular provider's network ranges were and then just used an online calculator like
https://ip2cidr.com/ to convert them to CIDR so my router would understand them)
This way, requests to that port from outside my network will get dropped if they aren't coming from the cellular network I plan to access it through.
Hopefully this helps someone.