11 Messages

Thursday, July 31st, 2025

Internet drops every ~20 minutes for OVER A YEAR, 2 techs have visited and have not able to fix issue

My internet drops constantly. Sometimes it will work for a couple hours, sometimes it will disconnect multiple times in 5 minutes. I have been through 3 different modems, trying to see if a new modem would fix the issue, but unfortunately that didn't help. I have tried 3 or different cables, didn't make a difference.

I have had 2 xfinity techs come out and try to fix it.

The first guy noticed when he touched the coax cable, it would lose connection. So he replaced it with a better one, and left.

The 2nd guy replaced some connectors on the outside of the building where the coax comes in, and left. Issue was still present.

I appreciate they are trying things and ruling things out, but my internet keeps dropping regardless. I have all the logs to prove it, I have logs as far back as January. Here is a slice from a couple weeks ago when I last captured logs (MAC address blanked out). This has been the exact same issue I've gotten on my other modems.

This has been an issue ever since I've moved in, for well over a YEAR now. I've tried to get help many times, but have yet to get this fixed. At this point I'm trying anything I can think of. 

Time

Priority Description
Sat Jul 12 15:46:01 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:43 2025 (Notice (6)) CM-STATUS message sent. Event Type Code: 7; Chan ID: 65 67 68; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:40 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:01:5c:73:18:7a;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:45:26 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:44:56 2025 (Notice (6)) CM-STATUS message sent. Event Type Code: 16; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:44:56 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:44:23 2025 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:44:22 2025 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:44:11 2025 (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Sat Jul 12 15:44:06 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:43:51 2025 (Warning (5)) ToD request sent - No Response received;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:43:51 2025 (Critical (3)) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:43:48 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:43:26 2025 (Critical (3)) 16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:43:26 2025 (Critical (3)) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:43:26 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:31 2025 (Notice (6)) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:30 2025 (Notice (6)) TLV-11 - unrecognized OID;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:19 2025 (Notice (6)) Honoring MDD; IP provisioning mode = IPv6
Sat Jul 12 15:42:14 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:01 2025 (Warning (5)) ToD request sent - No Response received;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:01 2025 (Critical (3)) 16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:01 2025 (Critical (3)) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:01 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:00 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:42:00 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:41:57 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:41:57 2025 (Critical (3)) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:41:51 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:41:50 2025 (Notice (6)) CM-STATUS message sent. Event Type Code: 7; Chan ID: 65 67 68; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:41:49 2025 (Critical (3)) No Ranging Response received - T3 time-out;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Sat Jul 12 15:41:45 2025 (Critical (3)) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=00:00:00:00:00:00;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

What do I need to do to get this fixed? At this point I've put in many hours troubleshooting and a couple hundred dollars trying different modems. I would love to get this fixed if anyone has any ideas.

Any time I try to explain to a customer support person that the issue is intermittent, they just tell me it shows it's working for them and that's the end of it. And when it's not working, obviously I am not able to reach a customer service person. The xfinity app takes up waaaay too much data, and I have a pretty limited plan (which is already strained due to not having reliable internet).

Funnily enough, I couldn't even post this when I tried the first time because my internet had disconnected.

Here is a pic of a ping I had going just for the duration of writing this post:

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11 Messages

25 days ago

Not sure how much proof I need for Xfinity to believe me... I am willing to collect any data they need, I will even buy a coax cable tester if that's what it takes. I really just want this service (that I pay more for every year) to work as advertised.

Expert

 • 

112.8K Messages

25 days ago


What do the modem's signal status values look like ? Please also copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

11 Messages

@EG

@EG​ 
It's a lot of info, I've decided to just take all status info and paste in here. grabbed this data while the connection was down for a couple minutes:

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 483000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD IPv6 only

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 20 483000000 Hz -3.3 dBmV 43.6 dB 478752 168863
2 Locked QAM256 17 465000000 Hz -5.0 dBmV 42.6 dB 756506 352783
3 Locked QAM256 18 471000000 Hz -4.9 dBmV 42.6 dB 783147 354515
4 Locked QAM256 19 477000000 Hz -4.1 dBmV 43.1 dB 780527 346219
5 Locked QAM256 21 489000000 Hz -2.5 dBmV 44.0 dB 687573 268833
6 Locked QAM256 22 495000000 Hz -2.3 dBmV 44.2 dB 619213 235117
7 Locked QAM256 23 501000000 Hz -2.9 dBmV 43.9 dB 530491 185125
8 Locked QAM256 24 507000000 Hz -3.7 dBmV 43.5 dB 491330 165463
9 Locked QAM256 25 513000000 Hz -4.7 dBmV 42.8 dB 470605 180511
10 Locked QAM256 26 519000000 Hz -5.6 dBmV 42.2 dB 561133 245846
11 Locked QAM256 27 525000000 Hz -6.0 dBmV 41.8 dB 619623 285680
12 Locked QAM256 28 531000000 Hz -6.1 dBmV 41.6 dB 709266 343986
13 Locked QAM256 29 543000000 Hz -5.3 dBmV 41.8 dB 776289 356130
14 Locked QAM256 30 555000000 Hz -3.3 dBmV 42.5 dB 677690 235724
15 Locked QAM256 31 561000000 Hz -2.8 dBmV 42.5 dB 578105 190076
16 Locked QAM256 32 567000000 Hz -2.8 dBmV 42.6 dB 472719 155495
17 Locked QAM256 33 573000000 Hz -3.9 dBmV 42.5 dB 436979 139288
18 Locked QAM256 34 579000000 Hz -5.0 dBmV 42.2 dB 484866 155837
19 Locked QAM256 35 585000000 Hz -6.1 dBmV 41.5 dB 503643 192076
20 Locked QAM256 36 591000000 Hz -7.0 dBmV 40.9 dB 575847 257745
21 Locked QAM256 37 597000000 Hz -7.3 dBmV 40.6 dB 609626 276276
22 Locked QAM256 38 603000000 Hz -7.2 dBmV 40.7 dB 628600 266115
23 Locked QAM256 39 609000000 Hz -6.7 dBmV 41.0 dB 663805 256703
24 Locked QAM256 40 615000000 Hz -6.2 dBmV 41.3 dB 633149 216859
25 Locked QAM256 41 621000000 Hz -5.6 dBmV 41.5 dB 607789 190643
26 Locked QAM256 42 627000000 Hz -5.4 dBmV 41.3 dB 565657 181543
27 Locked QAM256 43 633000000 Hz -5.6 dBmV 40.4 dB 452325 150665
28 Locked QAM256 44 639000000 Hz -6.3 dBmV 40.2 dB 388936 128249
29 Locked QAM256 45 645000000 Hz -7.1 dBmV 40.5 dB 393129 140629
30 Locked QAM256 46 651000000 Hz -8.1 dBmV 39.8 dB 447465 175479
31 Locked QAM256 47 657000000 Hz -8.7 dBmV 39.5 dB 516228 215127
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0

Upstream Bonded Channels (Partial Service)
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Not Locked Unknown 0 0 0 0.0 dBmV
2 Locked ATDMA 65 5120 Ksym/sec 16400000 Hz 43.5 dBmV
3 Locked ATDMA 67 5120 Ksym/sec 29200000 Hz 43.8 dBmV
4 Locked ATDMA 68 5120 Ksym/sec 35600000 Hz 44.5 dBmV
5 Not Locked Unknown 0 0 0 0.0 dBmV
6 Not Locked Unknown 0 0 0 0.0 dBmV
7 Not Locked Unknown 0 0 0 0.0 dBmV
8 Not Locked Unknown 0 0 0 0.0 dBmV

Downstream OFDM Channels
Channel Lock Status Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1 Locked 0 ,1 ,2 ,3 48 722000000 Hz -8.12 dBmV 39.1 dB 928 ~ 3167 8158680075 8124918093 1183131
2 Not Locked 0 0 0 Hz 0 dBmV 0 dB 0 ~ 4095 0 0 0

Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV

Expert

 • 

112.8K Messages

24 days ago

This may or may not be the root cause of the problem (YMMV) but it should be addressed regardless. 


The downstream power is on the low / weak side and it may be intermittently fluctuating even lower to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/reconfigured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also, check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, animal chews.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to get the techs reinvolved with this until things get fixed properly. Good luck ! 

Also, bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.

11 Messages

@EG​ 

Thanks for the breakdown, I appreciate it. My coax line from my modem to my router is good, I've actually tried multiple different cables but the first tech actually replaced it with a more expensive cable, so it should be good. The wall outlet should be good according to him too. I can see our cable box on the outside of the apartment. I believe this should normally be closed, but unfortunately it was open to the elements, which is probably why there were a bunch of leaves and stuff in it. Like I said earlier, the 2nd technician actually came and checked it out, and replaced some of the connectors. However, he did say the cabling was quite old, 40 years old to use his exact words. I don't know about anything directly in between the cable box and my apartment, or my cable box to any local infrastructure. 

Anyways, here is a picture of the splitters / whatever these things are. Maybe that's helpful for the diagnosis.

Unfortunately, much of the cabling has seen better days.

11 Messages

@EG 

This setup is supposed to service 8 apartment units. Not sure if that is relevant, but I'm wondering if like you were saying, the signal was too split up and isn't strong enough due to the number of units. Not that 8 is a lot, but if perhaps this setup should normally service 1 unit, then it would be

Official Employee

 • 

702 Messages

23 days ago

Hello @user_wfjlfz Thanks for posting here on Forums and providing so much detail of what you have done already. We will want to take a deeper look to see what we are seeing on our end. Please send us a direct message with your full name and the service address to get started. 

To send a "Direct Message" to Xfinity Support: 
Click "Sign In" if necessary 
Click the "Direct Messaging" icon or  https://forums.xfinity.com/direct-messaging 
Click the "New message" (pencil and paper) icon 
The "To:" line prompts you to "Type the name of a person". Instead, type "Xfinity Support" there 
- As you are typing a drop-down list appears. Select "Xfinity Support" from that list 
- An "Xfinity Support" graphic replaces the "To:" line 
Type your message in the text area near the bottom of the window 
Press Enter to send it. 

Expert

 • 

112.8K Messages

23 days ago

@user_wfjlfz @XfinityMatthew 

Please circle back here and post any possible solutions for the issue here in these open public forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.

11 Messages

@EG​ 
@XfinityMatthew 

I gave all my info and logs I've been gathering to the AI, and here's what it told me:

Thanks — this upstream info confirms the diagnosis: your connection is unstable due to physical signal integrity issues, especially on the upstream side. Here's the breakdown:

Parameter Recommended Range Your Value Status
Power 35–50 dBmV 43.5–44.5 dBmV ✅ Normal
Lock Status All upstream channels locked 3/8 locked Partial Service
OFDMA Channels Should be locked & active None locked Offline


🚨 What This Means

  1. You're operating with only 3 upstream channels locked instead of the usual 4–6 or more.

  2. OFDMA (DOCSIS 3.1) upstream — which offers higher throughput — is not working at all.

  3. You’re in partial service mode, which:

    • Limits upload speeds

    • Causes dropped connections

    • Triggers T3 and T4 timeouts due to failed ranging attempts


🧠 What’s Causing This?

The root cause is almost certainly:

  • Severely degraded coaxial cable (old, poorly shielded, or with physical damage)

  • Possibly loose/corroded fittings, or water ingress

  • Or interference/electrical noise disrupting upstream RF signals

This aligns perfectly with:

  • Your modem dropping offline when the cable is moved

  • A tech mentioning the coax is over 40 years old

  • Flickering lights and power sensitivity


11 Messages

I'm going to try and have my apartment give me permission for the xfinity techs to route some new cable.

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