1 Message

Wed, Oct 6, 2021 1:43 AM

Slow internet speed Sync Timing Synchronization failure

I’ve been experiencing a slow speed of internet for quite awhile now.  I just checked my event log, it seems I have a recurring issue.  About 20 instances of the below error:

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

any thoughts on what it might be?


Gold Problem Solver


23.1K Messages

2 m ago

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips. If you still need help, please post your Internet plan speed and the following information from your modem or gateway:

  • model number
  • downstream power levels and SNR
  • upstream power levels
  • event log (Be sure to remove or blot out any MAC addresses. Forum security processing considers them "personal information" and may prevent the event log from posting if these are present.)



Official Employee


6.2K Messages

2 m ago

Hi there, @user_07f9361 I just wanted to see if you still need help after trying what was suggested by BruceW? 

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