Hey @Finny,

We will need a bit more information about what your setup is looking like, and what you have done to troubleshoot/what problems are being seen.

First, what are the devices being used from your ISP? 

If your comcast device is also acting as a router, you will either need to configure the modem/gateway to use 'Bridge Mode', or you will need to configure your Archer Router in AP Mode - which will essentially serve to extend the network created and managed by comcast's gateway.

When in bridge mode, your Comcast gateway will work more as a traditional modem, in which you can connect one device to(your Archer Router) which will then manage the connections across the network.