SYNC Timing Synchronization failure - Loss of Sync

[oromero]

Hi there, 

During the last 2 or 3 weeks I have been having problems with internet with the service going offline and online randomly. I have tried everything including rebooting the router/modem several times, no service outages in the area, but things are getting worse. Today was a nightmare having to work from home and ended up using my phone to connect to the internet instead of my 1GB VM connection. I have also checked and cables are tightly screwed, and tried the usual things like reseting the modem, the router, etc. By the way, VM router is set as modem and I have an ASUS Zenwifi AIMESH wifi 6 XT8.

I have just looked a the network log (after a terrible day of poor internet service) and noticed a bunch of error messages, please see them below. Can you please let me know what I'm supposed to do? Shall I get in touch with customer service?

Thanks for your support

Oscar

Time	Priority	Description
20-10-2023 09:20:15	warning	DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-10-2023 09:20:15	notice	US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 11 13.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-10-2023 09:20:12	notice	REGISTRATION COMPLETE - Waiting for Operational status
20-10-2023 09:20:06	warning	REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-10-2023 09:20:01	notice	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-10-2023 09:19:58	notice	TLV-11 - unrecognized OID;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-10-2023 09:19:55	warning	DHCP WARNING - Non-critical field invalid in response ;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-10-2023 09:19:53	notice	Honoring MDD; IP provisioning mode = IPv4
20-10-2023 09:19:42	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
20-10-2023 09:19:41	critical	Cable Modem Reboot because of - HW or Power-On Reset
16-10-2023 17:41:29	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
16-10-2023 17:41:23	critical	Cable Modem Reboot because of - HW or Power-On Reset
16-10-2023 17:41:23	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
15-10-2023 22:33:45	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
15-10-2023 22:33:44	critical	Cable Modem Reboot because of - HW or Power-On Reset
15-10-2023 12:06:18	critical	Cable Modem Reboot because of - HW or Power-On Reset
15-10-2023 12:06:18	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
14-10-2023 22:23:14	critical	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
14-10-2023 10:49:15	critical	No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
14-10-2023 10:49:08	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
14-10-2023 10:49:07	critical	Cable Modem Reboot because of - HW or Power-On Reset
13-10-2023 23:51:43	critical	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
13-10-2023 17:39:28	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
13-10-2023 17:39:27	critical	Cable Modem Reboot because of - HW or Power-On Reset
11-10-2023 21:20:21	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
11-10-2023 21:20:20	critical	Cable Modem Reboot because of - HW or Power-On Reset
09-10-2023 17:02:05	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
09-10-2023 17:02:04	critical	Cable Modem Reboot because of - HW or Power-On Reset
09-10-2023 16:56:29	critical	Cable Modem Reboot because of - HW or Power-On Reset
09-10-2023 16:56:29	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
09-10-2023 11:32:51	critical	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.1;
09-10-2023 11:32:51	critical	Cable Modem Reboot because of - HW or Power-On Reset

[oromero]

Hi everyone, any idea on what to do here? thanks

[carl_pearce]

Looks like a local outage or potentially a hardware fault.

Check here (Run the additional test):

https://www.virginmedia.com/support/help/service-status/identification

[WorstISP]

This is most likely an upstream issue. It's affecting many Virgin customers but unfortunately you're going to have to jump through hoops to get them to look at it.

I've been having the same issue for 3 months, and they're just ignoring it now and refusing to respond.

[oromero]

Hi carl_pearce thanks for this. I have tried this multiple times, rebooting the modem, tested connections, and the same outcome. I think I'll call them when I have the strength to spend long time on the phone waiting. I'll circle back if/when I manage to get this sorted.

[oromero]

thanks WorstISP  sorry to hear you are going through the same. I'll try with customer service and keep you posted if/when this is sorted. cheers

[oromero]

Also going through the forum came across this interesting post 

https://community.virginmedia.com/t5/Speed/Hub-status-data-understanding-network-log-messages/td-p/4...

I guess this means that:

SYNC Timing Synchronization failure: Broadly speaking the most serious connection failure, where the hub cannot detect the synchronisation data that is transmitted by the CMTS every 20 milliseconds.  As a result the hub loses synchronisation with the CMTS, usually all internet connectivity is lost, and the hub has to renegotiate all channels from scratch, taking about 7 minutes to do this.  This usually takes as long as, and to a user looks like the modem has spontaneously rebooted.

it'd be good if VM is able to provide more clarity on why this is happening. There are a bunch of messages in the forum about similar patchy service level.

Thanks and look forward to hearing from a VM in the forum.

cheers

[WorstISP]

I suspect that it's happening because they're selling more bandwidth than they can actually provide. They're splitting lines to multiple homes, so what happens is when a few people are using a lot of bandwidth on a shared line, there's signal contention and you get knocked offline.

They should know that this is an issue, it's an issue being widely reported across the UK right now. However when the last technician visited (this was the 4th to come out), I found out that they don't actually keep any records of service faults, or take note of anything. So every time you get a technician out, they're coming in blind, same for their customer support. They don't actually document anything, so as far as they're concerned, once you've got online once they mark the ticket as "resolved". The technician who came out didn't even know that the issue was affecting the entire building, not just me.

Their whole support process is set up to help people with their Wifi, there's genuinely no way to get them to fix upstream issues, and they refuse to acknowledge that they exist.

This means that Virgin Media's support team are incapable of solving intermittent issues like the one we're facing. I know some people working in Virgin Media who tell me this is due to poor management who are putting pressure on support staff to close tickets as quickly as possible rather than keeping them open and acknowledging that some issues are more complicated than others.

Anyway, you shouldn't expect this issue to ever be resolved. Look for some other providers. I've heard good things about Plusnet and Hyperoptic.

[Beth_G]

Hi oromero

Thank you for your post. Sorry to hear you've been having some trouble with your broadband connection!

I've had a look at this end and all your power levels are looking normal and within spec. I've been unable to check the Samknows data from here due to an error, though. Do you happen to be in modem mode at all? If so, can you please pop into router mode and let us know? This is so we can run further diagnostics 😊

Have things improved at all over the weekend and yesterday? 

[oromero]

hi Beth,

Thanks for the message and getting back to me. That's correct, this is setup in modem mode since I have an Asus mesh wifi6 xt8 installed at home. The signal seems a lot better now, but I'll keep an eye in the next few days and circle back.

Cheers

Oscar