Default Unable to connect to server

I've looked around and can't find anyone else with this problem. I am unable to connect to my PC using my dyndns address through any apps, but I can ping it in terminal emulator fine, and I can connect using it on my laptop. I can also connect using the WAN IP or local network IP if I'm on the network. I'm only having this problem on my M8, and it's both Wi-Fi and mobile. Has anyone else had this problem or have any suggestions?