Xfinity app can't find my modem

See if anything here is still valid. YMMV;

Connect it to the coax line and power it up. Let it fully sync up with the system, and check that the front / top panel indicator light(s) are steadily lit. 

Then connect a computer to it and open up a browser. You *may* see their *Walled Garden* modem self registration page. If so, follow the screen prompts. Have your mobile telephone number, your Xfinity username and password, or the account number and telephone number associated with your Comcast account handy.

If not, try calling 1-855-652-3446. That is their self-install device activation line.

If that doesn't work for you, you can call 1-800-comcast and tell a rep that you would like to have a new modem provisioned for service. Have the RF / CM / HFC MAC address and the serial number of it handy when you call.

Could you please send our team a direct message with your full name and full address? Our team can most definitely take a further look at this issue. To send a "Peer to peer" ("Private") message:
Click "Sign In" if necessary
• Click the "Peer to peer chat" icon
• Click the "New message" (pencil and paper) icon
• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
• Type your message in the text area near the bottom of the window
• Press Enter to send it

@user_b48cb8 

Did you have a chance to try any of those modem activation methods ?

I’m having the same issue, we’re u able to figure out the problem? It says on mine have wait 48 hours once I start it up but my US DS light is flashing. 

@Kaylalayla09 

Please create a new topic of your own here on this board detailing your issue. Thanks.

For future reference, it is better to submit your own post as it creates a ticket to get help, and posting on an old thread can delay getting help.