Device was great for about a week. After that I started to have frequent T3 errors which can be a few things but after trouble shooting it appears to be either the Ethernet cable provided or the modem itself. Going to try to return as this I ordered the 3.0 instead of the 3.1 on accident anyway. Bummed because for the first few days this thing was great.Update 9/11/23Everything was good with the replacement I received for about 24 hours then it died again. This time I can't log into the modem to see anything. Service appears fine. Getting a flashing globe with up and down in blue. Going to send this one back as well. Don't buy this one.

The modem, advertised by Amazon as supported by Comcast and also on the Comcast list of supported hardware, could not be activated and added to my Comcast account.The Xfinity activation app could not find the modem at all, and Comcast support could not manually activate it because the MAC id on the modem did not match any devices in the Comcast hardware database.Update -- as suggested by Comcast support, I returned the modem for another unit (same model). I got the same result when trying to activate it.Comcast suggested that I contact ARRIS technical support and have them send Comcast the range of MAC ids covering this model. Nothing like dumping the ball in the Consumer's lap.I did contact ARRIS, and all they could tell me was perhaps the modem was actually used and registered to an existing account. They suggested only buying direct from ARRIS in the future. They had me do a factory reset, which accomplished nothing. So I also returned the second modem.I've just purchased a refurbished version of the same model from Amazon. Hopefully, it's old enough that the MAC id is actually in the Comcast hardware database. If not, it'll get returned, and I will purchase something directly from ARRIS.

I wasted 4 hours trying to get this activated and got an Ethernet adapter only to find out the specific MAC address simply isn't supported by Xfinity, so now I have to get a new one. Customer support also non existent... if you get this you should get a backup modem from Netgear just in case.

I bought this only for it to be returned because the product literally does not have a valid MAC address

Constantly drops connection.

This unit is NOT Xfinity compatible! I spent more than one hour on the phone with Xfinity to learn that, though ARRIS claims this item works with Xfinity Internet, it does not. I am returning it for a full refund and will likely not purchase an Arris modem. My first clue that this item would not be as advertised should have been that the box arrived with no outer packaging and that the yellow/orange seal on the wrapper was torn making it obvious that the product box had been opened. Very poor and unprofessional. ARRIS, you have just lost another consumer. I should have paid attention to the ten percent negative reviews.

This unit is NOT compatible with Xfinity; although the label says it is. It is listed on several sites as compatible as well. After much angst with calling Xfinity. It was a no-go. I contacted Arris as well. They swore up and down that this device is compatible with Xfinity..so who knows what the real truth of this matter is.

This modem worked for about 6 months, then completely died and won’t turn on. Total piece of junk!

I should have read all the reviews about the issue with Arris not connecting to xfinity. However, I didn’t read the reviews, and I ended up with the same problem. Do not bother wasting time or money on this modem because it’s comparability with xfinity is not guaranteed.

Appeared to be set up correctly but would not transfer data. App kept asking me to allow it to scan my local network to mine personal info. Another garbage device that is just trying to collect data to sell.