Changed Coax>Ethernet, Signal Goes In and Out

[MS113]

Hi all,

Just changed my Fios Internet from Coax to Ethernet using the very helpful guide on here. Unfortunately, even with a much better router than the rental, the signal for both the 5G and 2.4 are very weak, and the connection goes in and out every 5 minutes or so. Never had this problem before. The new router I have is the Linksys MaxStream AC1900. When it works, the connection is amazing, but then it goes to "not connected". This happens to both 5G and 2.4. Tried resetting router, no firmware updates are available, connections are solid and all wires are good. What do I do?