Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, bad/old/cheap connectors, or corroded connections. Replace them if you do.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

do you have a screen snip of the cable connections page and the event logs? 

I’ve already checked and replaced any bad connection. The cable coming into my house is connected to a connector to the wire that goes into the house. Then another barrel connector in the network box (not splitter) and the last one is the one at the wall out let. All of those a good. 

Not just “good” but you’ve actually unscrewed them and checked to see if there was any moisture, foil touching copper, kinks in the line, etc? 

Do you have a screen snip of the cable connections page and event logs? 

Yes, I replaced all crimped style connector with compression fitting. I even bought all the tools for it and I made sure the foils and wires are not touching the middle copper piece 

Here the screen shot of my modem signals 

It appears to be a common problem with DOCSIS 3.1 modems, at least I had the same problem with both a Motorola MB8611 and an Arri SB8200 replacing a Motorola SB6141  Had 5 onsite visits by more than a dozen Comcast “technicians” none of whom were able to diagnose or offer repair suggestions or remedies.  Comcast reported their monitoring showed my modem ALWAYS online while on my end I had zero internet service.  I eventually was pointed to an article by Brady Volpe of the Brady Firm discussing this very issue.  Rather than fool around with the reported DOCSIS 3.1 issue which Comcast obviously did not understand, I acquired an Arris SB6190 DOCSIS 3.0 modem which I will install once I return home.  

See https://broadbandlibrary.com/ofdma-2/

Please keep me updated if that fixes your issue 

You do have errors in your line and your power technically in spec but a bit lower than I like to see. 

You’ve moved it to right where the line comes into the home and connected it? This ensures it isn’t wiring within the home or connector thats causing the issue

I’ve tried that before and yea I was getting the same signal. I’ll double check it today when I get home. I went ahead and order another modem Sb6190 that is a DOCIS 3.0 

Docsis 3.0 doesn’t have the speed capability of docsis 3.1. And most ISP’s are dropping the speed tiers that they’ll support for docsis 3.0. I’d be working more with the ISP to get the line issues fixed or figuring out if its a modem issue versus dropping down to a 3.0 device. 

For now I’ll see if it is docsis issue. Zito media uses docsis 3.0 and the max speed they have for me is 200Mbps. If it doesn’t work I’ll just return it to Amazon.

Hope it works well for you!

Thanks very much.  The old Motorola DOCSIS 3.0 modem was working well and I should probably have left it alone but I had the hots for a new 3.1 modem which turned out to be a disaster.  I left A T & T 21 years ago and went to Comcast because of lousy internet connections and don’t know how A T & T is doing with DOCSIS 3.1 modems but in my area there are lots of complaints by Comcast customers with the same problem I had and no help from Comcast, so I wonder whether there is something inherent in 3.1 modems or perhaps limited to Comcast.

ATT is either on fibre or on DSL. Not aware of att using any current cable setups. I’ve had great luck with docsis 3.1. But i have had to have comcast out to prove to them that it was their line and not my modems after I tried 2x different modems and had the same issue. Turns out a tree had kinked the line in the ground and they had to re-run it. 

Thats far better than my Comcast experience…..I had the same problem a few years ago which eventually turned out, after 7 onsite visits to tell me my hardware was old and must be replaced, to be a break in the cable behind 2 or 3 houses down the street and one that section of cable was replaced the problem was solved.  Usually an onsite visit by Comcast “technicians” is primarily an attempt to con me into renting their hardware.

My problem was that I had scheduled two appointments for technicians to come out and both times they didn’t. 

So the technician came out and said it’s the node problem. Everything is working now, getting 200Mbps down 20up. Now all down stream are all in 40snr but upstream was sitting at 51-52. I hooked up the active return amp from arris BDA-42-1-AR-R and all upstream are down to 40. Not sure if I should leave it on there (I got it when I was desperate trying to fix my internet)