WiFi devices show "connected, no internet" (wired connection unstable too)

Start here;

https://forums.xfinity.com/t5/Your-Home-Network/Internet-Troubleshooting-Tips/m-p/3310447#M316652

EDIT: just got a text from my wife who, after I remotely restarted the gateway, is no longer able to get an internet connection at all (wireless or wired).  I hope Comcast is going to pay for the marriage counselor....

OK.

This has been going on for about the past 6 weeks, but keeps getting worse.

No recent changes in service other than whatever the new security service that got added (but it was pushed, I didn't do it).

The equipment shows as Technicolor CGM4140COM but it looks nothing like the graphic.  The back of the modem shows X86-T.   The bottom of the device has a PN of CGM4140COM. As far as I can tell it is compatible (it came from Comcast) and not at End of Life.

Devices exceed minimum requirements (except for the Win 8 computer, but that is seldom used).

I've reset the gateway over, and over, and over, and over, and over, and over again.  Including a reset to factory specs w/ Comcast support activating it immediately afterward.

Lights on the front are fine.

I am not at home so I cannot test the signal strength. I would ask my wife, but she is desperately trying to work from home with what has become a wildly unreliable network.

Cabling and fasteners: nothing has changed (nothing added, nothing changed, nothing moved)

All the F connectors that I know of compression.  They were all installed by Comcast.

All the splitters that I'm aware of were installed by Comcast.  Last I checked, they were all fine.

Speed test last night (wired) was about 500Mbps (Gigabit speed).  There is a Gigabit switch between one desktop and the modem.  The other one is directly connected to the back of the modem -- this is the one that cannot connect properly today. (My cell phone could get connected to the network, but no internet was available - or the connection to the internet bounces up and down).

All security software is disabled on my phone (which, by the way, is working just fine on a Comcast wireless network at my office.)

Since I'm not home I cannot run a ping or tracert.

I will have to grab the logs and run a ping/tracert tonight when I get home.  Assuming my wife doesn't strangle me when I walk in the door.

Matt

I've been having similar issues with my new XFi gateway, often at times of the day or week that might be high-traffic (Sunday afternoon seems to be the worst for some reason).   Last Sunday the XFi app said there was an outage in my area, and in fact my Voice and TV were also down, but supposedly it only lasted 4 minutes, while my intermittent internet connection issues (on multiple wifi devices) kept up even after restarts and connection checks. I finally gave up and went outside to read a book, and everything was working a few hours later.

Today was a day like several others since getting this new gateway (I added the Voice service last month,  dumping CenturyLink for my landline).   I was using the internet on my desktop for some email and moderate online chores (no streaming) when it started lagging, then hourglassing, then no connection.   Also no internet on the laptop (right next to the gateway)  or phone.  However, the app reported no outages, and even thought the internet was dead in the water, the Voice phone line had a consistent dial tone, and the TV was fine. 

I had to switch my phone to cell-only to use the app.  I restarted the gateway, checked all the connections (coax on the gateway and at the wall), powercycled (ie: unplugged for the recommended 12 seconds per the app) restarted the gateway again.  Each time I tried something, it seemed like it connected again for a minute, then it would drop out again.   Again - Voice service working fine except during the restarts, of course.   

Today Xfinity agreed to send me another new gateway.  The chat agent couldn't figure out why there was no signal, but after two restarts from her end, the connection returned and has been stable since then.  Doesn't mean she did anything, because the same thing has happened every time before now - it eventually came back on its own.  At one point she suggested that I clear my cache.  Seriously?  On which of three devices that can't connect?  I didn't try talking to Alexa today, but I have on other days, and of course it's also dead in the water when this happens.  

Will another gateway fix this?  I'm not convinced.  BTW, this is the new one that doesn't allow you to change the channel or choose which band to use - whenever I look at my wifi analyzer it's on 2.4ghz, and the channel is the same as my immediate (condo) neighbors.    When my connection first comes back, the speed test reports a blazing 300+ mbps, but it doesn't last.  It deteriorates and slows down until I'm at about 30 (sometimes single digits)  then I'll have another day like today.   

What a waste of time.

Did anyone find an answer to this? What are we paying premium prices for? It's not like this is a discount service. Service standards are getting low...

I am having this issue now. It just started a few hours ago. I turn the modem off and on and i get some service. Then nothing. I already know calling Comcast in the morning is not going to be fun. And all they will do is send a tech and it sounds like when u get this problem, it doesn't seem to get fixed. 

This problem just started for me about 5 hours

I started having the issue this morning. I spent 30 minutes on the phone with customer service and have an appt to swap out modems. I’m not optimistic it will work after reading other comments but I’ll see if a tech will need to come out or not.

@user_cd1df9 @purpledawg

Please create new topics of your own here on this board detailing your issue. Thanks.  Year old dead now being closed.