I detached a 3rd party extender from the xfinity router and moved upstairs.
after this 2 computers, an ipad and a peloton bike no longer can connect to the internet properly. One computer is fine. The strange thing is the computers that are not working correct have perfect connections to GOOGLE< Netflicks, facebook but almost nothing else. So there can connect to the wifi signal but are limited to the larger sites. On the internet these are the ipn6 encription website.
New Customers (or switching modems) make sure Comcast has the HFC-MAC (CM-MAC) as your modem MAC.. If they get the CPE-MAC (WAN-MAC) the modem will not work correct and your CPE will only get a IPv6 address..
I am finding this is most of the issues I have found..