Nighthawk AC1900 C7000v2 continuously disconnects

[boxingfan48]

Hi!

We've had this Netgear Nighthawk AC1900 Cable Modem Router Model: C7000v2 router for about 2 years now and it's been reliable 90-95% of the time but lately it has gotten more inconsistent with holding onto a connection. The ethernet connection is generally stable, but over wifi we have problems. It seems to freeze and slow to a crawl multiple times throughout the day and sometimes stops altogether for 10-15 minutes. Randomly our modem/router will reboot, maybe once every week or two like it's struggling to stay alive.

I've checked the firmware and it's up to date for our Spectrum ISP, but I looked into the router logs and discovered a whole list of alerts I didn't know existed. I'm hoping the community can help point me toward my next steps on solving this. Our physical coaxial connection to the modem is solid and the modem location hasn't changed since we moved in, so it's not like it should be a wifi trouble spot all-of-a-sudden. I recently changed the channels for our wifi because the other ones were clogged with building neighbors, but that didn't seem to cause any issues. Anyway, below I've copy and pasted what I found in the router logs. (It goes on like this forever I imagine) Thanks for any advice!

2020-7-8, 09:34:59	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:34:59	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:35:00	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:35:11	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:35:12	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:35:15	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:35:31	Notice (6)	Overriding MDD IP initialization parameters; IP provisioning mode = IPv6
2020-7-8, 09:35:40	Error (4)	Missing BP Configuration Setting TLV Type: 17.8;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:35:40	Error (4)	Missing BP Configuration Setting TLV Type: 17.9;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:39:40	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:39:43	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:39:45	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:39:50	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:39:51	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:39:55	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:39:57	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:40:06	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:42:13	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:42:16	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:42:17	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:42:23	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:42:24	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:21	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:21	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:26	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:30	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:31	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:34	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:41	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:46	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:47	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:52	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:54	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 09:44:58	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 10:41:19	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 10:41:20	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 10:41:23	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 10:41:25	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 10:41:58	Warning (5)	MDD message timeout;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;
2020-7-8, 10:42:01	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:03:cc:48;CMTS-MAC=00:01:5c:6a:76:4c;CM-QOS=1.1;CM-VER=3.0;

[FURRYe38]

Have the ISP check the signal and line quality UP to the modem. 
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem.