I have a Motorola SB 6120 modem and a D-Link dual band router that has worked fine.
I just had HORRIBLE problems trying to connect a Netgear AC 3200 router to the modem, as well as the Asus AC2400. Neither router can get get an internet signal from the modem, even though the modem acts like things are fine (solid blue send/receive, online in green, link light lighted in blue). On the Netgear, I couldn't even directly login to the router.
I let the Asus sit with the modem for 10 minutes and it still couldn't get the internet signal. I'm able to re-establish my connection to the D-Link within 10 seconds.
Should I try up to 30 minutes to see they will shake hands? Reset the modem through the modem page at 192.168.100.1?
Thanks to any and all