Serviio

Got a new AT&T modem/router that has built in firewall. On my old one I had the Serviio working just fine on external devices like my phone and tablet and I've set the port forwarding to the TCP 23424 just like my old one but every time I try to connect using the IP address, it fails to make a connection. Works internally on tv's and computers if I use the localhost or computer name but not with the IP. When I try to Check connectivity status in Serviio console I get x's on insecure and secure connection where I used to get green check marks. I am no expert in any of this but I feel like I've done everything just the way I did before and it's not working. Any help would be greatly appreciated.