^
It sounds as if your various devices may be getting their IP addresses from different places. Normally your main router should be running a DHCP server, and all other devices should be configured to get their IP addresses via DHCP from that server. And if you have other Wifi access points on the LAN you should make sure that these are NOT running a DHCP server (indeed those access point should themselves be configured to get their own IP addresses from the DHCP server on the main router).
If you have more than one DHCP server, then different devices will get their IP addresses from different servers. So there will be conflicts. And if the IP addresses are on different subnets their traffic will not be routed properly. Furthermore some routers will not route traffic where they themselves have not issued the IP address.
Ideally, furthermore, once you have got a stable IP address allocation scheme, you should then set the IP addresses on the DHCP server as being “reserved” to the device that currently holds that address. This prevents devices from moving about the address table, and makes things more stable. However do not start making reservations until you already have a stable scheme — otherwise you risk (p)reserving a mess.
Once you have set the router and all devices to use DHCP, you should power cycle all of them. Start by turning all devices off. Then turn on your cable modem (if any); wait 2-3 minutes for it to start, then turn on your router; and wait another 2-3 minutes for IT to start; then turn on your WiFi access points; and wait etc.; and finally turn on all the other wired and wireless devices.