Inexplicable Network Problem

This problem has had me wanting to pull my hair out for days, so here goes.

First, let me describe my network set up in order to make this a bit more straight forward. We have two buildings on our property separated by a drive way. One of them acts as an office, one is the place we sleep. The office is where our Google Fiber comes in, and is also where our modem is housed. We have a 155 foot Cat6 line that runs from the modem, across the driveway, and into our house which connects directly into a Linksys dual band wireless router. There are 4 Ethernet ports in the basement of our house that are directly connected to this Linksys router as well.

So here is our issue. We have a variety of wireless devices and wired devices on our home network, but only some of them properly connect to the internet. The devices that don’t connect properly return a “IP address could not be obtained” error.

I can not figure out for the life of me what is the issue.

DHCP is turned on on both the modem and on the Linksys router. Does this matter? What other settings could cause this problem?

I was on the phone with the Linksys people for two hours troubleshooting to no avail.

If there are anymore questions you need answered, ask away! I am really really not having a good week because of this bullshit internet.

I should also note that we have had this same issue on 3 different routers, and the Google modem was replaced 4 days ago.