Hi,

Yesterday, if I tried to browse the web, the browser would just hang, but now everything seems to be fine. This happens every now and then. All of the lights on the modem were green. This modem is on their support modems list. An XFinity tech came down and said that the signal they're putting out is fine. They made the cable connection to our apartment more secure, and I don't see any loose connections. The firmware on the modem (pushed by the ISP) is the latest version. I checked out the modem's config page for errors in the log, and I found this:

Time	Priority	Description
2024-2-26, 20:18:59	Warning (5)	Dynamic Range Window violation
2024-2-26, 20:18:45	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:28	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
1970-1-1, 00:00:21	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-2-26, 19:52:04	Critical (3)	Resetting the cable modem due to docsDevResetNow
2024-1-16, 18:29:59	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-1-16, 18:29:58	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-1-16, 18:29:55	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-1-16, 18:29:54	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-1-16, 18:29:53	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-1-16, 18:29:52	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-1-16, 18:29:49	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2024-1-16, 18:29:47	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2024-1-16, 18:29:46	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2024-1-16, 18:29:11	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2024-1-16, 18:29:04	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2024-1-16, 18:28:58	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2024-1-16, 18:28:55	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-12-20, 23:35:05	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-12-18, 01:20:26	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-12-11, 08:57:48	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-11-16, 10:48:29	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-11-16, 10:48:17	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-11-11, 16:29:49	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:21	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-25, 10:44:04	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-10-25, 10:31:04	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-10-25, 09:55:47	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-25, 09:55:33	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
2023-10-25, 00:04:09	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:21	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-10, 17:45:56	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:21	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-10, 14:46:04	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-10, 14:45:58	Critical (3)	No UCDs Received - Timeout;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-10, 14:45:39	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-10, 14:45:38	Critical (3)	No UCDs Received - Timeout;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-10, 14:45:19	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2023-10-10, 14:45:18	Critical (3)	No UCDs Received - Timeout;;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:56:25	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=bc:a5:11:f1:aa:64;CMTS-MAC=00:90:f0:5b:04:00;CM-QOS=1.0;CM-VER=3.0;

The error at the top from yesterday (2024-2-26) is the most relevant, but I provided the whole log to help with context. I think the fifth error down is when XFinity was resetting the modem since I gave them a call.

Finally, these are my modem's metrics:

Do these look normal?

Any help is greatly appreciated. I work from home, so I need my internet to be reliable. Thank you.

Forum Discussion

CM500-100NAS intermittently slow internet