CM1200 modem NOT WORKING with nighthawk r7000 router

[BDot310]

Ok so i have had spectrum all of 2020 with my modem and router working perfectly fine. Last week my router just started not being able to pull a signal from my modem. And when the times it does it lasts for about 10 minutes. I have tested the modem and connected my comp to it and it works fine but when i connect the ac1900 router to it then it works like 50% of the time.

I have checked the mac address on the router and it is using the default one. I have also power cycled the modem then the router to be sure that the modem syncs up with the routers mac address. Can anyone help me out?

[plemans]

How long did you run it with just modem---pc to ensure the modem connection was good? 

What firmware is on the r7000? its not exactly known for the best firmware

[BDot310]

I ran it for an entire day. I have had this setup for an entire year with no problems until last week. Yesterday i installed the latest firmware 1.0.11.116 Which was just released on 1/28/21. I installed it after the problems started. I go into the nighthawk dashboard and it says no internet connection to the router. Then i will power cycle the modem and router a few times then it will work for 10-30 min at speeds rather slow then drop out of nowhere. The modem will be fine at speeds of 400+ mbs.

[plemans]

The R7000 has had firmware issues. The agreed upon stable version is 1.0.9.42

If this happened after the firmware update, you can always try a factory reset and a clean install. (not from backup)

If that doesn't help, then I'd try downgrading the firmware