Friday, September 29th, 2023 1:59 AM


Does S33 work on comcast?

I purchased an Arris S33 modem from Amazon. I connected it and got a blue light but when I used the activation on the app, it would fail almost immediately and tell me to chat with support. I spent 45 minutes on the phone with support and they weren't able to resolve it. They said they would call back but never did. I called Arris support and they couldn't solve it either so said it was probably the modem and i should return it. I then went to best buy and bought another S33. This time the activation didn't fail immediately but after 10 minutes said it couldn't find my modem. I tried a few more times moving upstream on coax connections until I got to the coax coming directly into the house. Still couldn't find the modem. How am I supposed to get this modem to work?

2 Messages

10 months ago

I'm having this same issue right now with a brand new S33 failing to be located during the app activation. I spent 30 minutes on the phone with xfinity last night, and they were unable to "see" the modem as well and were convinced I was giving them the wrong MAC. They entered a ticket for something "back of house" to "add the MAC to the system" so that I could activate it, and they indicated this would take 12-24 hours. It's been over 24 hours, I still cannot activate the modem, and I owe xfinity a follow up call. I'll try a modem reset before calling them just for fun.

I logged into the modem hoping there was a fluke with the sticker not matching the MAC, but the internal web portal shows the same MAC as the sticker. 

No it shouldn't take 12-24 hours activation only take 20 minutes or less... between s33 is an good modem see an big increase

2 Messages

I spent another hour on the phone with support today. The person I worked with today indicated the reason it wasn’t working was my account was tied to the Xfinity Xfi gateway I was trying to replace. That had to be removed from my account for the S33 to work.

Whether that was the cause or not, I had everything up and running by the end of the call.

1 Message

I was trying to replace a Xfinity gateway with an Arris S33 too. The phone tech could not remove the Xfinity gateway because my package had Comcast voice phone service included which I never used. The S33 is not a voice capable modem, so the Comcast computer system would not allow the tech to remove the Xfinity gateway. Voice service came bundled in my package 2 years ago (which I did not care if it was in the bundle because the package lowered my monthly bill).

I had to talk to a different support person to change my package which got the voice service off my account. Support was then able to remove the Xfinity gateway from my account. I was then able to activated my S33 with the Xfinity App.

Thank you user suraklyn for pointing me in the right direction with this issue. It did take a lot of time on the phone with 2 different support people. I hope this helps others that might have issues switching from an Xfinity gateway to your own modem.

Official Employee


3.6K Messages

Hi user_hgenbl, thanks for reaching out on our Forums with this feedback, much appreciated. We value you as a customer and I do apologize for any inconvenience or frustration we may have caused you with that process. Please be sure to reach out to us for any future issues or concerns, my team is here to support you. 


I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick



104.7K Messages

Topic closed.

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Official Employee


1.1K Messages

10 months ago

Hello @user_132a97, thanks for reaching out for help with your modem. 

As long as the device is showing up on https://www.xfinity.com/support/devices/, it should be compatible with our network. If you follow that link, enter your address, then select your speed tier, you can see all the devices that we have tested and approved to work with our services. 

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