That depends on Your ISP, currently most ISPs uses CG-NAT to share bandwidth. I personally have Static IP and also IPv6 that is solution for CG-NAT due the fact that each Device on LAN directly connect to internet.
I also have paid hosting plan that allows me to DDNS my IP and have domain to access my MM. The results are that I can access MM5 DLNA server and play tracks.
Try opening port on router be that Forward or DMZ. Enter IP address and port you get from http://checkip.dyndns.org/
onto Phone browser and if no info is shown and your router is set correctly then you are most likely behind CG-NAT.
https://www.purevpn.com/blog/how-to-che ... orms_CGNAT