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Suspected drop outs causing Teams calls to fail

Joining in

Hi all,

I am on the M125 speed broadband, and I work from home regularly.  We use Microsoft Teams for work calls and I’ve noticed that when on calls it frequently hangs, sometimes the video then kind of fast forwards as it catches back up, but more often it just drops the call altogether.

I have run the basic diagnostics on the line to try and determine if I have faults, the only one I am seeing from the router logs is detailed below.

I run the Hub 3.0 in modem mode.


Here are the Hub details:

Standard specification compliant: DOCSIS 3.0
Hardware version: 10
Software version: 9.1.2109.200



The faults I’m seeing in the logs are as follows:

21:42:32Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
31/03/2023 21:42:32criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
31/03/2023 21:42:32Warning!RCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
31/03/2023 21:42:31criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

I have checked all cables/connections and everything appears to be secure.

Please can you advise next steps in helping me to resolve this issue?

many thanks,




Very Insightful Person
Very Insightful Person
What router are you using? What is supplying your wifi?

Do the issues happen only on wifi connections or do you see them at the same times on devices connected on ethernet cables? If you don't know, can you check to help diagnose whether it is just a wifi issue or it could be network connection/Hub related?


I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired, 2 on WiFi) Hub5 in modem mode with Apple Airport Extreme Router +2 Airport Express's & TP-Link Archer C64 WAP. On Volt 350Mbps, Talk Anytime Phone, x2 Mobile SIM only iPhones.

Forum Team
Forum Team

Good Morning @Alihawk78, thanks for your post on our Community Forums, and a very warm welcome to you!

Sorry to hear of the recent issues you've been experiencing with the connection to our broadband services.

If you're able to confirm the answers to the questions posted by @jbrennand, that would be a great starting point for us to work with.

Kindest regards,