Because you are using DHCP, it assigns an IP adress to your computer(s) for a given period of time. So if you used gaming and application to open TCP and UDP ports for your assigned IP adress, then when the IP changes, the application stops.
Access your router http://192.168.1.1
log in and go to port forwarding and open the ports that needs to be opened for your application, and check the timing in the status section. Note remove the settings you may have inserted in your gaming and application>ports>IP, only one application per port.
Check every detail of your router, the problem and solution are there.