CM500 Cable Modem Downstream Constantly Flashing Green

After checking the cables I find no erosion ordamaged cables, and I do not have any splitters, signal attenuators, and amplifiers. 
the modem is as close to the coax entry point as physically possible. 

Could there be a damaged line outside? 

I speed test and i get acceptable speeds yet sometimes a website on my desktop will show a DNS failed page buit then within seconds suddenly appears to load the page....

I have attached a screen capture of the connections page