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

Frequent Visitor

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

EDIT: changed Subject to show that the wired connection instability is no longer occasional.


I posted this in response to someone else's issue but figured I should raise my own issue here since I am not able to chat w/ an Xfinity employee due to COVID19 work from home issues at Xfinity.


My WiFi connections frequently show that my devices (phones, tables, laptops) are "connected, but no internet".  Gateway restart temporarily fixes the issue.  Online diagnostic tool tells me that something is wrong that may be impacting my internet experience and offers to restart the gateway.  This just keeps happening over and over and over again.   Preventing me from working from home, which is less than ideal during a quarantine...


Gigabit service

X86-T modem

Wireless devices are 2 Android phones, 1 Android tablet, 2 iPhones, 2 Windows 10 laptops, 1 Windows 8 laptop, 1 MacBook pro (not all online at the same time.)


Hardwiring seems to reduce, but not eliminate, the issue.


I also get an occasional "cannot assign IP address" but that is far less frequent.


I have reset the X86-T to factory defaults and had Comcast activate it.  No change.


Restarting the gateway appears to help for a time, then the issue comes back.


Any suggestions?




Re: WiFi devices show "connected, no internet" (wired connection issue on occasion too)

Start here;

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Frequent Visitor

Re: WiFi devices show "connected, no internet" (wired connection issue on occasion too)

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....




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.




New Poster

Re: WiFi devices show "connected, no internet" (wired connection issue on occasion too)

Did you ever resolve this? We have the same thing happening. We lost WiFi abilities, replaced our router, and that didn’t work. We got an xfinity modem/router so they would actually troubleshoot and sent a tech and now nothing hardwired will connect, and only half the WiFi connections work.
They sent a tech out who checked all the connections and said they are working. So he left because he said his job was done.
Troubleshooted with them for 6 more hours on the phone and it seems their only solution is to restart the modem over and over.
Regular Visitor

Re: WiFi devices show "connected, no internet" (wired connection issue on occasion too)

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.

New Poster

Re: WiFi devices show "connected, no internet" (wired connection issue on occasion too)

Any more info on this appreciated as I have the same issue. Replacing modem did nothing