Are you connecting to the correct IP ? Is it setup as IP Cameras or Wirecast(ed) cams, meaning are they a setup browser exclusive application. Also are you able to connect to each IP Cam individually using the app?
When within the network I can find each IP by using IP cam, which will show me a list of the camera's IP's.
I can then either type their IP and port into the address bar of Firefox or other browsers or I can type in the DYN address and the correct port and it will ask for ID and password and open up the software of the camera which allows all settings, etc.
On my phone I can use the web browser and log in to the camera/software or use the preset app. IPcam viewer by Robert Chou and after ID and password it will bring up all cameras which have been preset into the software for this app using my dyn address and ports so that it will always work if comcast changes my IP at the home router..