CM500 ethernet light blinking amber when connect the R612 wifi router

[Ddan-X]

I change the wifi router to R6120, and CM500 ethernet light blinking amber, But if connnect the old wifi router, CM500 ethernet light is green. why I change my old wifi router, because it link speed only 150 mbps. 

I tried ethernet connect my computer, also ethernet light is amber.

internet status is good. but speed is low, only got 80 mbps out of 400 mbps.

how to fix this situation? 

[plemans]

the R6120 isn't a gigabit router. Its only a 10/100mbps devices. 

if you read the cm500's manual, if the ethernet port is amber, it means it only has a 10/100mbps connection which would correspond to your router. 

[plemans]

https://www.netgear.com/support/product/R6120.aspx