Computer losing wired connection for a couple seconds and reconnects

I've recently been experiencing an issue that's most noticeable while I am playing games. The ethernet is losing connection for a couple seconds and reconnecting (The ethernet icon on the bottom right shows a red X for a couple seconds and my game freezes). It happens sporadically and I am not sure what is causing the problem.

Here are the things I have tried:

1. Updated BIOS
   2. Updated Ethernet Drivers
   3. Tried both ethernet ports on the motherboard.
   4. Restarted computer, router, and modem.
   5. Updated router firmware.
   6. Run full virus scan

Anybody have any idea?

PC: Win 10 64 bit Ethernet Intel & Killer ethernet

Router: UniFi USG

Model: Arris 8100

The connection from my pc: -> Unmanaged Switch -> Router

The network connection flicking can have a lot of reasons. In most cases I have seen the reasons were:

• bad patchcord (replace it)
• bad contacts (clean and straighten them)
• NIC damage (replace it or, if it is on-board, disable it and add new discrete one)

And in some cases the connection speed fixing (remove auto-negotiation from NIC and/or commutator port settings) helps.