I'm helping a customer, who has Armstrong internet and owns an Archer A8.  Since Armstrong just upgraded his equipment today, we could not get a connection from the fiber modem to the WAN port on the A8.  The old Armstrong box worked fine, so it's odd that the router wouldn't "see" the new modem.  What's interesting is that I took an old router with dd-wrt, and it connected with no issues.

Does anyone have an idea as to why the TP-Link won't "talk" to the new Armstrong fiber connection?  By the way, I did speak with Armstrong business tech support, and the agent was just as puzzled as I.  Also, the A8 will pick up an IP from my home Nighthawk router and allow a connection from the computer in another room in my house, which is wired to the Nighthawk.