Netgear Nighthawk AX8 (CAX80)ISP: Comcast (Xfinity)Hardware Version: 1.01Firmware Version: V1.1.0.36Cable Firmware Version: V1.02.08 Trying to get the new CAX80 up and running, replacing my C6300 modem router. Unfortunately it's having issues going through the activation process.My old C6300 still works and I remember it had working out of the box with my Xfinity service, so a little bummed that this wasn't as seamless as I hoped. For the CAX80, the online activation through the Comcast Xfinity web interface didn't work for me, nor did activation through contacting their tech support.All I get is "Your modem is offline. Please check the RF connection."The upstream/downstream lights were able to turn solid white, but the online light would never stop flashing. I'm told by Netgear tech it means that it was able to get a link, but unable to get assigned an address, so the issue is probably on Comcast side.Has anyone seen this issue? I've tried both contacting Comcast (to see if they can activate by giving them the MAC address) and Netgear (to verify if they had any insight as well) for support but there was only so far I could get with the low level of support they are able to provide. Maybe because it's the weekend, but I didn't feel very confident that the support was that great.I'm just confused because I figure if my old modem still worked (and still does), there shouldn't be anything preventing the CAX80 from getting activated either. Unless there is some difference in signal requirements between the two modems?I've switched back to my trusty C6300 temporarily until a solution is found. Getting an Comcast Xfinity tech to come by tomorrow but am hoping there was a way to avoid it, or at least an idea of what the issue is before tomorrow, cause not knowing is driving me a little crazy.I figure if this doesn't get resolved, I'll just refund it and refrain from upgrading my internet setup for a while.

The fact that your old modem works still shows the problem. They would have had to delete this MAC to put in the new MAC. So unless you had them change it back in their system, your old modem would not be working.Try http://192.168.100.1 to see if you can get into your old modem. Post your signal strengths and signal qualities here (basically all information that is measured in db, dbm, or dbmv).

Contact your ISP for activation help and information. Some ISPs require the ISP to activate a new modem.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. Be sure to power OFF the modem for 1 minute them back ON.jdimailig wrote:Netgear Nighthawk AX8 (CAX80)ISP: Comcast (Xfinity)Hardware Version: 1.01Firmware Version: V1.1.0.36Cable Firmware Version: V1.02.08 Trying to get the new CAX80 up and running, replacing my C6300 modem router. Unfortunately it's having issues going through the activation process.My old C6300 still works and I remember it had working out of the box with my Xfinity service, so a little bummed that this wasn't as seamless as I hoped. For the CAX80, the online activation through the Comcast Xfinity web interface didn't work for me, nor did activation through contacting their tech support.All I get is "Your modem is offline. Please check the RF connection."The upstream/downstream lights were able to turn solid white, but the online light would never stop flashing. I'm told by Netgear tech it means that it was able to get a link, but unable to get assigned an address, so the issue is probably on Comcast side.Has anyone seen this issue? I've tried both contacting Comcast (to see if they can activate by giving them the MAC address) and Netgear (to verify if they had any insight as well) for support but there was only so far I could get with the low level of support they are able to provide. Maybe because it's the weekend, but I didn't feel very confident that the support was that great.I'm just confused because I figure if my old modem still worked (and still does), there shouldn't be anything preventing the CAX80 from getting activated either. Unless there is some difference in signal requirements between the two modems?I've switched back to my trusty C6300 temporarily until a solution is found. Getting an Comcast Xfinity tech to come by tomorrow but am hoping there was a way to avoid it, or at least an idea of what the issue is before tomorrow, cause not knowing is driving me a little crazy.I figure if this doesn't get resolved, I'll just refund it and refrain from upgrading my internet setup for a while.

I am having the exact same issue with Cox in Arizona. Router loses the Internet connection 1-2X per day and I have to reboot to get it back. Cox came out and replaced my cable line just to be sure, said they are not seeing any timeouts or packet loss and the signal levels are all in range. Is this the table you're referring to? Cable ConnectionCancel ApplyFrequency start ValueThis field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.Starting Frequency Startup ProcedureProcedureStatusCommentAcquire Downstream Channel783 MHzLockedConnectivity StateOKOperationalBoot StateOKOperationalSecurityEnabledBPI+ Downstream Bonded ChannelsChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables1Locked256 QAM1783000000 Hz0.6 dBmV39.3 dB9372141122Locked256 QAM33357000000 Hz3.2 dBmV40.5 dB1703Locked256 QAM2789000000 Hz0.5 dBmV39.1 dB151828394Locked256 QAM3795000000 Hz0.2 dBmV39.0 dB5705Locked256 QAM4801000000 Hz0.0 dBmV38.8 dB7906Locked256 QAM5807000000 Hz0.0 dBmV38.8 dB9107Locked256 QAM6813000000 Hz0.0 dBmV38.7 dB8908Locked256 QAM7819000000 Hz0.2 dBmV38.8 dB9409Locked256 QAM8825000000 Hz0.2 dBmV38.7 dB909176710Locked256 QAM9831000000 Hz0.1 dBmV38.6 dB38191411Locked256 QAM10837000000 Hz0.0 dBmV38.4 dB738154312Locked256 QAM11843000000 Hz0.2 dBmV38.4 dB82013Locked256 QAM12849000000 Hz0.4 dBmV38.3 dB130014Locked256 QAM13855000000 Hz0.4 dBmV38.3 dB122015Locked256 QAM14861000000 Hz0.0 dBmV38.1 dB141016Locked256 QAM15867000000 Hz0.0 dBmV38.1 dB158017Locked256 QAM16873000000 Hz0.1 dBmV38.2 dB136018Locked256 QAM34363000000 Hz3.1 dBmV40.7 dB22019Locked256 QAM35369000000 Hz2.7 dBmV40.7 dB52020Locked256 QAM36375000000 Hz2.6 dBmV40.6 dB18021Locked256 QAM37381000000 Hz2.7 dBmV40.7 dB23022Locked256 QAM38387000000 Hz2.7 dBmV40.7 dB58023Locked256 QAM39393000000 Hz2.6 dBmV40.7 dB64427624Locked256 QAM40399000000 Hz2.2 dBmV40.6 dB13025Locked256 QAM41405000000 Hz2.1 dBmV40.6 dB12026Locked256 QAM42411000000 Hz2.1 dBmV40.5 dB73027Locked256 QAM43417000000 Hz2.2 dBmV40.6 dB53028Locked256 QAM44423000000 Hz2.3 dBmV40.6 dB41029Locked256 QAM45429000000 Hz2.1 dBmV40.5 dB73030Locked256 QAM46435000000 Hz2.0 dBmV40.5 dB56031Locked256 QAM47441000000 Hz2.0 dBmV40.6 dB173032Locked256 QAM48447000000 Hz1.9 dBmV40.6 dB1730 Upstream Bonded ChannelsChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower1LockedATDMA62560 Ksym/sec12900000 Hz30.5 dBmV2LockedATDMA15120 Ksym/sec17700000 Hz27.8 dBmV3LockedATDMA25120 Ksym/sec24100000 Hz29.3 dBmV4LockedATDMA35120 Ksym/sec30500000 Hz30.0 dBmV5LockedATDMA45120 Ksym/sec36900000 Hz31.0 dBmV6Not LockedUnknown0000.0 dBmV7Not LockedUnknown0000.0 dBmV8Not LockedUnknown0000.0 dBmV Downstream OFDM ChannelsChannelLockStatusModulation /Profile IDChannelIDFrequencyPowerSNR /MERActive SubcarrierNumber RangeUnerroredCodewordsCorrectableCodewordsUncorrectableCodewords1Locked0 ,1 ,2 ,3159300000000 Hz7.48 dBmV43.0 dB1108 ~ 298791755335421027095682Not Locked000 Hz0 dBmV0 dB0 ~ 4095000 Upstream OFDMA ChannelsChannelLock StatusModulation / Profile IDChannel IDFrequencyPower1Not Locked000 Hz0 dBmV2Not Locked000 Hz0 dBmV Extended Upstream Transmit PowerEnable Extended Upstream Transmit Power Current System Time:Fri Sep 18 12:55:27 2020System Up Time:05:21:15

jesmith602 Please post Event Logs + Logs as well (two different pages.yes, this is the table.

CAX80: Modem is offline - Please check RF connection

14 Replies

icaruspony
Luminary
Aug 02, 2020
The fact that your old modem works still shows the problem. They would have had to delete this MAC to put in the new MAC. So unless you had them change it back in their system, your old modem would not be working.

Try http://192.168.100.1 to see if you can get into your old modem. Post your signal strengths and signal qualities here (basically all information that is measured in db, dbm, or dbmv).
- Betachem
  Aspirant
  Nov 17, 2020
  Same issue here in Seattle but worse. I have woken up a couple of times and lost all my SSID’s on the device. All replaced with a version of Broadcom 2.4g or Broadcom 5g SSIDS. Called netgear they claimed they didn’t do it, called xfinity and they claimed they didn’t do it either. However this has happened twice. About once every two weeks the router goes down and I get the cannot connect to cable message and to check my rf settings. This is getting really old. This unit was supposed to work with xfinity and all I have is issues.
FURRYe38
Guru - Experienced User
Aug 03, 2020
Contact your ISP for activation help and information. Some ISPs require the ISP to activate a new modem.
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.
Be sure to power OFF the modem for 1 minute them back ON.
jdimailig wrote:
Netgear Nighthawk AX8 (CAX80)
ISP: Comcast (Xfinity)
Hardware Version: 1.01
Firmware Version: V1.1.0.36
Cable Firmware Version: V1.02.08

Trying to get the new CAX80 up and running, replacing my C6300 modem router. Unfortunately it's having issues going through the activation process.

My old C6300 still works and I remember it had working out of the box with my Xfinity service, so a little bummed that this wasn't as seamless as I hoped. For the CAX80, the online activation through the Comcast Xfinity web interface didn't work for me, nor did activation through contacting their tech support.

All I get is "Your modem is offline. Please check the RF connection."

The upstream/downstream lights were able to turn solid white, but the online light would never stop flashing. I'm told by Netgear tech it means that it was able to get a link, but unable to get assigned an address, so the issue is probably on Comcast side.

Has anyone seen this issue? I've tried both contacting Comcast (to see if they can activate by giving them the MAC address) and Netgear (to verify if they had any insight as well) for support but there was only so far I could get with the low level of support they are able to provide. Maybe because it's the weekend, but I didn't feel very confident that the support was that great.

I'm just confused because I figure if my old modem still worked (and still does), there shouldn't be anything preventing the CAX80 from getting activated either. Unless there is some difference in signal requirements between the two modems?

I've switched back to my trusty C6300 temporarily until a solution is found. Getting an Comcast Xfinity tech to come by tomorrow but am hoping there was a way to avoid it, or at least an idea of what the issue is before tomorrow, cause not knowing is driving me a little crazy.

I figure if this doesn't get resolved, I'll just refund it and refrain from upgrading my internet setup for a while.

vkdelta

NETGEAR Employee Retired

Aug 04, 2020

pls post DOCSIS Connection table and Event log

jesmith602

Apprentice

Sep 18, 2020

I am having the exact same issue with Cox in Arizona. Router loses the Internet connection 1-2X per day and I have to reboot to get it back. Cox came out and replaced my cable line just to be sure, said they are not seeing any timeouts or packet loss and the signal levels are all in range.

Is this the table you're referring to?

Cable Connection

Cancel Apply

Frequency start Value

This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.

Starting Frequency

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	783 MHz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enabled	BPI+

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectables
1	Locked	256 QAM	1	783000000 Hz	0.6 dBmV	39.3 dB	9372	14112
2	Locked	256 QAM	33	357000000 Hz	3.2 dBmV	40.5 dB	17	0
3	Locked	256 QAM	2	789000000 Hz	0.5 dBmV	39.1 dB	1518	2839
4	Locked	256 QAM	3	795000000 Hz	0.2 dBmV	39.0 dB	57	0
5	Locked	256 QAM	4	801000000 Hz	0.0 dBmV	38.8 dB	79	0
6	Locked	256 QAM	5	807000000 Hz	0.0 dBmV	38.8 dB	91	0
7	Locked	256 QAM	6	813000000 Hz	0.0 dBmV	38.7 dB	89	0
8	Locked	256 QAM	7	819000000 Hz	0.2 dBmV	38.8 dB	94	0
9	Locked	256 QAM	8	825000000 Hz	0.2 dBmV	38.7 dB	909	1767
10	Locked	256 QAM	9	831000000 Hz	0.1 dBmV	38.6 dB	381	914
11	Locked	256 QAM	10	837000000 Hz	0.0 dBmV	38.4 dB	738	1543
12	Locked	256 QAM	11	843000000 Hz	0.2 dBmV	38.4 dB	82	0
13	Locked	256 QAM	12	849000000 Hz	0.4 dBmV	38.3 dB	130	0
14	Locked	256 QAM	13	855000000 Hz	0.4 dBmV	38.3 dB	122	0
15	Locked	256 QAM	14	861000000 Hz	0.0 dBmV	38.1 dB	141	0
16	Locked	256 QAM	15	867000000 Hz	0.0 dBmV	38.1 dB	158	0
17	Locked	256 QAM	16	873000000 Hz	0.1 dBmV	38.2 dB	136	0
18	Locked	256 QAM	34	363000000 Hz	3.1 dBmV	40.7 dB	22	0
19	Locked	256 QAM	35	369000000 Hz	2.7 dBmV	40.7 dB	52	0
20	Locked	256 QAM	36	375000000 Hz	2.6 dBmV	40.6 dB	18	0
21	Locked	256 QAM	37	381000000 Hz	2.7 dBmV	40.7 dB	23	0
22	Locked	256 QAM	38	387000000 Hz	2.7 dBmV	40.7 dB	58	0
23	Locked	256 QAM	39	393000000 Hz	2.6 dBmV	40.7 dB	644	276
24	Locked	256 QAM	40	399000000 Hz	2.2 dBmV	40.6 dB	13	0
25	Locked	256 QAM	41	405000000 Hz	2.1 dBmV	40.6 dB	12	0
26	Locked	256 QAM	42	411000000 Hz	2.1 dBmV	40.5 dB	73	0
27	Locked	256 QAM	43	417000000 Hz	2.2 dBmV	40.6 dB	53	0
28	Locked	256 QAM	44	423000000 Hz	2.3 dBmV	40.6 dB	41	0
29	Locked	256 QAM	45	429000000 Hz	2.1 dBmV	40.5 dB	73	0
30	Locked	256 QAM	46	435000000 Hz	2.0 dBmV	40.5 dB	56	0
31	Locked	256 QAM	47	441000000 Hz	2.0 dBmV	40.6 dB	173	0
32	Locked	256 QAM	48	447000000 Hz	1.9 dBmV	40.6 dB	173	0

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	6	2560 Ksym/sec	12900000 Hz	30.5 dBmV
2	Locked	ATDMA	1	5120 Ksym/sec	17700000 Hz	27.8 dBmV
3	Locked	ATDMA	2	5120 Ksym/sec	24100000 Hz	29.3 dBmV
4	Locked	ATDMA	3	5120 Ksym/sec	30500000 Hz	30.0 dBmV
5	Locked	ATDMA	4	5120 Ksym/sec	36900000 Hz	31.0 dBmV
6	Not Locked	Unknown	0	0	0	0.0 dBmV
7	Not Locked	Unknown	0	0	0	0.0 dBmV
8	Not Locked	Unknown	0	0	0	0.0 dBmV

Downstream OFDM Channels

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power	SNR / MER	Active Subcarrier Number Range	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	0 ,1 ,2 ,3	159	300000000 Hz	7.48 dBmV	43.0 dB	1108 ~ 2987	917553354	210270956	8
2	Not Locked	0	0	0 Hz	0 dBmV	0 dB	0 ~ 4095	0	0	0

Upstream OFDMA Channels

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power
1	Not Locked	0	0	0 Hz	0 dBmV
2	Not Locked	0	0	0 Hz	0 dBmV

Extended Upstream Transmit Power

Enable Extended Upstream Transmit Power

Current System Time:Fri Sep 18 12:55:27 2020

System Up Time:05:21:15

vkdelta
NETGEAR Employee Retired
Sep 19, 2020
jesmith602 Please post Event Logs + Logs as well (two different pages.
yes, this is the table.

FURRYe38
Guru - Experienced User
Sep 28, 2020
Any progress on this? Or did you give up?
jdimailig wrote:
Netgear Nighthawk AX8 (CAX80)
ISP: Comcast (Xfinity)
Hardware Version: 1.01
Firmware Version: V1.1.0.36
Cable Firmware Version: V1.02.08

Trying to get the new CAX80 up and running, replacing my C6300 modem router. Unfortunately it's having issues going through the activation process.

My old C6300 still works and I remember it had working out of the box with my Xfinity service, so a little bummed that this wasn't as seamless as I hoped. For the CAX80, the online activation through the Comcast Xfinity web interface didn't work for me, nor did activation through contacting their tech support.

All I get is "Your modem is offline. Please check the RF connection."

The upstream/downstream lights were able to turn solid white, but the online light would never stop flashing. I'm told by Netgear tech it means that it was able to get a link, but unable to get assigned an address, so the issue is probably on Comcast side.

Has anyone seen this issue? I've tried both contacting Comcast (to see if they can activate by giving them the MAC address) and Netgear (to verify if they had any insight as well) for support but there was only so far I could get with the low level of support they are able to provide. Maybe because it's the weekend, but I didn't feel very confident that the support was that great.

I'm just confused because I figure if my old modem still worked (and still does), there shouldn't be anything preventing the CAX80 from getting activated either. Unless there is some difference in signal requirements between the two modems?

I've switched back to my trusty C6300 temporarily until a solution is found. Getting an Comcast Xfinity tech to come by tomorrow but am hoping there was a way to avoid it, or at least an idea of what the issue is before tomorrow, cause not knowing is driving me a little crazy.

I figure if this doesn't get resolved, I'll just refund it and refrain from upgrading my internet setup for a while.

Forum Discussion

CAX80: Modem is offline - Please check RF connection