Need help with internet connection for Netgear CAX30 AX2700 on Xfinity

[josephsk2]

Hello,

I'm having an issue with internet connection for Netgear CAX30 AX2700 on Xfinity.

Our cable modem router had been working fine until Friday, 9/17 around afternoon the internet got disconnected, and we were not able to figure out what's going on. Currently, the downstream icon is keep blinking and will not go further. We tried plugging power off and on, resetting, checking and rechecking connections, turning off wifi and then trying ethernet cable, but none of them seemed to work. I called Xfinity, and they said their side is working fine, and looks like we need to pay for asking for tech to come. We'd like to first rule out if this is a cable modem router problem before calling for Xfinity tech. I will include our event logs, and I'd really appreciate if someone can help us (I've also attached our full logs):

Time	Priority	Description
1970-01-01 00:00:29	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
1970-01-01 02:43:59	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:41:22	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:41:17	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:40:05	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:40:05	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:40:05	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:40:04	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:40:02	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:40:02	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:37:36	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-17 09:37:32	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 04:49:06	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 04:48:43	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 04:48:42	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 04:48:42	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 04:43:29	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 00:01:32	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 00:01:32	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 00:01:32	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-16 00:00:24	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-15 15:12:18	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-13 16:03:46	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 22:02:16	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 21:59:35	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 21:59:34	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 21:59:34	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 21:58:26	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 18:12:38	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 15:18:04	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 15:18:02	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 15:18:02	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 15:16:55	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 12:55:27	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 12:55:26	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 12:55:26	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 12:51:41	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 10:57:59	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 10:57:57	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;
2021-09-12 10:57:57	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=94:a6:7e:d4:d1:1c;CMTS-MAC=00:01:5c:86:96:46;CM-QOS=1.1;CM-VER=3.1;

[FURRYe38]

Please post a copy and paste of the modems connection status page.
Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
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. 
Be sure to power OFF the modem for 1 minute them back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...

[plemans]

Do you have a screen snip of the cable connections page? 

your logs are indicating line issues but the cable connections can help as well. 

do check your coax line for kinks, damage, old/bad/loose/corroded/sketchy connections and replace them if you have them. 

Also remove any splitter, signal attenuators, or amplifiers if you have them and try. 

[josephsk2]

Hello!

Thanks for the reply, @FURRYe38 !

I've attached modems connection status page.

Update on our side, we tried replacing coax cable and powering off the modem for 1 min, and it didn't work. We borrowed my friend's modem - which works great at his home with Xfinity with no problem - and installed it here, but similar symptom - downstream icon beeping.

We live in a huge apartment complex, and we are wondering if the line at the maintenance room started not working (we had a flood about 2-3 weeks ago (but not on our floor) and there had been some reconstruction).

[josephsk2]

Hello!

Thanks for the reply, @plemans !

I've attached modems connection status page.

Update on our side, we checked coax cable, and even tried with new coax cable. We do not use splitter, attenuators, or amplifiers. We borrowed my friend's modem - which works great at his home with Xfinity with no problem - and installed it here with new coax cable, but similar symptom - downstream icon beeping.

We live in a huge apartment complex, and we are wondering if the line at the maintenance room started not working (we had a flood about 2-3 weeks ago (but not on our floor) and there had been some reconstruction).

[plemans]

I'd be betting its something with the line as not a single channel is locking. If you've checked what lines you can, then the isp noeeds to checking it.